Chosen Solution
I just got an iPad 9th gen. digitizer to replace my broken one, though it didn’t come with pre-applied adhesive. I can’t find anywhere the strips for the iPad 9, so I was wondering if I could just buy and use 8th or 7th gen adhesive strips
That’s what I would do. Hardware layout for these 3 models is extremely similar, and I have found other listings which indicate cross compatibility between them for digitizer adhesive. If all else fails, you can custom cut adhesive tape to fit. It’s just a MUCH bigger hassle. But that’s what many people did in the “olden times” before precut adhesive became more widely available. I have used this tape for other repairs of the same sort with a pretty good success rate.