Best weapon for a bladesinger is a quarter staff or club?

Quote from Xalthu >>

As a level 17 wizard, wouldn’t you rather cast meteor swarm? Or horrid wilting, or prismatic spray? 
Heck, at a total of 7d6+(intx2), assuming you hit both times, you’re probably better off going with a fireball that catches at least 2 targets.

 Meteor Swarm is great.   Horrid wilting is nice damage but the area is small and some creatures are immune.  Only really worth it against plants/water elements.   Prismatic Spray SUCKS.  only a 1 in 8 chance of being worth it for damn dex save.  Should have been 1d10 with 3 in 10 chance of double damage, with a 30 ft range.

8th level try sunburst or illusory dragon.  7th level  try whirlwind, force cage, reverse gravity 

For discussion about 9th level spells I would say Time Stop is best for Bladesinger. You can use it and then spend a few turns buffing yourself and activating things like your bladesong and shillelagh. Mirror Image, Haste, Blink, Crown of Stars - whatever you can get for however many extra turns you have. Sure, you'd only get them for 7 turns or so, but most battles don't last that long anyway and you're going to be very suddenly strong. You can save yourself one of those limited extra turns by using Contingency with the condition of "when I cast Time Stop". You can have Haste and Blink be Signature Spells to reduce spell slot use (more to use for defensive features/spells) and Mirror Image can be a Mastered spell to cast infinitely without spell slots so you can re-up it whenever you want (and still get to make an attack thanks to Haste, which can still be a cantrip thanks to special feature of extra attack). 

To the enemy you basically went Super Saiyan.