So, I'm interested in looking at which 9th level spells would be the best when playing a Bard. I know Wish is almost universally considered the one to pick though, so I'd rather just consider it a default, and look at the NEXT best spells.
This seems plenty powerful. I've not seen it in action, but advantage on pretty much everything, disadvantage for attacks against you, and all for 8 hours with no concentration? I have a hard time seeing how any Bard spell beats this.
Most other non-Bard 9th level spells either have suitable Bard-accessible substitutes (Power Word Heal instead of Mass Heal, Resurrection instead of True Resurrection, etc.) or seem a bit limited (such as Weird.) But there's no substitute for Meteor Swarm. City-destroying damage from a mile away... what's not to like?
Prismatic wall. More damage than meteor swarm, several conditions, and it's a non-concentration, no-friendly-fire hazard that lasts 10 minutes. On the other hand, the range and area are much, much smaller. It depends on what you expect to need from your 9th-level spells.