This spell is great if you combined it with abilities like Alchemical Savant and Elemental Affinity.

Does each meteor affect nine squares (one square for the meteor, and each square adjacent) or does it affect 4 squares (with the meteor landing on an intersection and having a 5-ft radius)?

I think technically both are right, I believe they intentionally left it open to interpretation to give a little more freedom on how you want to use it. I think it's ultimately up to you and your DM on how it gets used.

Im confused is 1d6 per meteor or 2d6 per meteor I get a little loss in that part

1d6 * 6 = 36 max

2d6 * 6 = 72 max

So here's how this spell works

You create 6 meteors, +2 meteors for every spell-slot level above 3rd. You can use a bonus action on your turn to cause up to 2 meteors to shoot towards a point you chose within range and detonate upon reaching this spot. A meteor does not have to impact a solid object to detonate, but will detonate early if it impacts an object between the caster and its intended point of detonation.

Each meteor does 2d6 fire damage to creatures in a 5-foot radius (10-foot diameter sphere).

Each meteor is saved against separately, even if they are thrown to the same spot.

Damage for each meteor is rolled for separately, even if they are thrown to the same spot.

The meteors are not classified as attacks and thus would not be affected by abilities that increase attack damage, or affected by abilities/bonuses that are activated by making an attack.

The spell ends after 10 minutes, or when you loose concentration regardless of if you have used all meteors or not.

Quote from ChaseHarbak >>

How does this spell interact with the necrotic damage of Bestow Curse? does each bonus action deal damage, or each individual meteor?

Not possible, as both spells are concentration, they would not be able to be cast by the same spellcaster at the same time.

Quote from RebeccaTheWizzard >>

Does each meteor affect nine squares (one square for the meteor, and each square adjacent) or does it affect 4 squares (with the meteor landing on an intersection and having a 5-ft radius)?

When using a grid you normally chose a 5-ft-square not an intersection when "choosing a point" to affect. thus it would be the first option (9-squares with the point of detonation in the center), however you can also choose a point in space and not the ground or wall to attempt to utilize a more 3-dimentional area of effect.

See here for more info - https://www.dndbeyond.com/sources/basic-rules/spellcasting#Targets 

Quote from Samt1995 >>

Im confused is 1d6 per meteor or 2d6 per meteor I get a little loss in that part

1d6 * 6 = 36 max

2d6 * 6 = 72 max

 2d6 per meteor. Minimum 6 meteors @ 3rd level (72 max) with a maximum of 18 meteors @ 9th level (216 max)

I believe the area of effect is 2x2. It has the same wording as "moonbeam" and that has been confirmed as a 2x2 aoe. The key word is "point."

Imagine reskinning this as tiny pixies who fly around you, and then on your command hurl themselves at the enemy, exploding in a ball of flame.

I know it’s in the book but hypothetically this should increase your ac or do damage if a NPC comes into melee range, right?

the meteors circle around you so hypothetically a ranged attack may hit the meteor? 
If you were GM/DM would you let of fly? I get it overpowers the concentration if you’re just un-hit-able….

if my player character flavored it right I would let it slide 

or maybe as a reaction the meteor hits a melee character but then you’re both making DST to dodge the 5ft impact?

If you upcast bestow curse at 5th level or higher it does not require concentration, so it should technically work then.

Cast this spell if you have a wand of fireballs on you.  Two words:  FIREBALL SPAM!!!   I'm going to use that on my players.  Not to kill them, duh, but to annoy them and mess them up.    

Interestingly I just realized this spell does not rely on sight. It just says "a point within range" not "a point within range that you can see" like many other spells do. So you can throw meteors into the middle of magical darkness, a thick sandstorm, etc. where you think enemies are hiding.

Quote from brettjustbrett >>

I know it’s in the book but hypothetically this should increase your ac or do damage if a NPC comes into melee range, right?

the meteors circle around you so hypothetically a ranged attack may hit the meteor? 
If you were GM/DM would you let of fly? I get it overpowers the concentration if you’re just un-hit-able….

if my player character flavored it right I would let it slide 

or maybe as a reaction the meteor hits a melee character but then you’re both making DST to dodge the 5ft impact?

 

 Mechanically, the spell only does what is in its description. Any uses not covered by the rules is a conversation for you to have with your DM when the situation arises. 

Magic item just give it to the Paladin.

MY FAVOURITE SPELL 🤩

Quote from RebeccaTheWizzard>>

Does each meteor affect nine squares (one square for the meteor, and each square adjacent) or does it affect 4 squares (with the meteor landing on an intersection and having a 5-ft radius)?

When using a grid you normally chose a 5-ft-square not an intersection when "choosing a point" to affect. thus it would be the first option (9-squares with the point of detonation in the center), however you can also choose a point in space and not the ground or wall to attempt to utilize a more 3-dimentional area of effect.

See here for more info - https://www.dndbeyond.com/sources/basic-rules/spellcasting#Targets 

First, I'd like to point out how great RebeccaTheWizzard's response is. It's incredibly informative and nails how this spell works!

There is one minor correction I'd like to make on the point above, however - unless a spell has a range of self, or specifically refers to "within 5 feet of you," then all other instances of "within 5 feet" refer to a 5-foot radius, which is a total of 10-foot diameter sphere. So at most, this spell can affect four squares (2x2) when using a grid system.

The grid system does allow for choosing the intersection points that are connecting four squares, which is precisely what needs to be done in order to maximize the area of this spell.
This can be counterintuitive since spells like Thunderclap, which state "within 5 feet of you" affect the 8 squares surrounding you on a grid system, but it is how spells like Melf's Minute Meteors and Call Lightning work.

fireball is 8d6, this spell over the course of 3 turns is 12d6 fire damage, every 2d6 requires another saving throw. this is a concentration spell, and therefore makes me believe this is a balanced spell, essentially a sidegrade to fireball. Fireball is a damage now spell, but the meteors spell is a damage over time thing. the thing that makes up for it tho is that if your target is 120ft away from you, they'd have to dash twice to get to you, by then you have used all your meteors, and (on each turn besides the first) also cast yet another spell. another reminder is that these meteors float around you, not the point it was cast, so they move with you. you can dash, move 60 feet, and then pelt something for 4d6 damage because that is a bonus action. I think it is a great constant damaging spell that would be made overpowered if it used d8s

I Changed this spell a bit on my table:
 Changed the Casting time to 1 BA
 Requires no Concentration
 only 1 meteor can be shot at once

This in my opinion makes it similar to spiritual weapon which i think the original version is a little underwhelming especially because it is concentration.

The classes that get this get so many more potent concentration spells.

I love the flavor of this spell and wanted to do it justice.

I'm using this as the basis for a Living Spell.

Not very experienced with the game, but a question. Can you stack this spell? As in can i cast it twice and have 12 meteors at hand (for 2 lv3 spell slots)? In that case, can i expend 2-4 meteors at a time for some quality carnage?

Quote from Jackkabuki >>

I Changed this spell a bit on my table:
 Changed the Casting time to 1 BA
 Requires no Concentration
 only 1 meteor can be shot at once

This in my opinion makes it similar to spiritual weapon which i think the original version is a little underwhelming especially because it is concentration.

The classes that get this get so many more potent concentration spells.

I love the flavor of this spell and wanted to do it justice.

 Sounds to me like you nerfed it rather than "do it justice".

This spell is 1Action which means you can launch two meteors the same turn it is cast since they are launched as bonus actions. This means the real spell can be cast and do 4D6 all in the same turn. In your version you have to cast it one turn and then do 2D6 on the second round. So, while it uses my concentration, I can do 12D6 damage in 3 rounds. You can only do 4d6 in the same time. It would take you 7 rounds to do max damage, but I guess you got to keep your concentration in exchange for more than doubling the time it takes to dish out damage.