I've been running a third-party grip on my 90D for a while and honestly its been super solid. You definitely dont need to spend a fortune on the official Canon one just to get through a wedding. I picked up the Neewer NW-90D Vertical Battery Grip for Canon 90D 80D 70D and i'm really satisfied with how it holds up.

• The shutter button is actually quite tactile and doesnt have that mushy feel some cheap ones do.
• Build quality is sturdy enough that it doesnt flex much when im using a heavy flash.
• I havent run into any of those weird battery drain issues lately. It basically doubles your shooting time which is huge for a long day. If you need it fast, its a safe bet that works well and feels decent in the hand. Let me know if you need help with it.

^ This. Also, over the years I've tried many cheap grips and the Vivitar VIV-PG-80D Battery Grip for Canon EOS 90D is actually decent for the price. I grabbed one as a backup last year and it feels surprisingly solid in the hand. Shutter is clicky, not mushy. Ngl, those battery drain rumors are mostly from people using knockoff cells. For under fifty bucks, you'll be fine for that wedding.