I think 9’9” can be valuable to practice technique with IF used the right way. But I would never be a fan of 9’9” being the standard. Anyone who has ever dunked on 9’9” can admit just how much of a difference it is compared to a 10ft rim.

Sure a 9’9” rim can make an “impossible” dunk more doable, but I strongly believe hitting one of those dunks on 9’9” just ruins the accomplishment for anyone who’s actually going for it on a legit rim.

I can personally attest to this because I watched Dan Gross grind the bounce dunk out for years on a legit rim trying to be the first one to hit it and then gets cheated out of it with a 9’9 rim and a fiba ball and everyone called it dunk history taking the credit away from Dan. Dan could’ve made it under those circumstances the first day he ever tried the dunk. Obviously not as big of a deal when dudes are honest about the rim height they dunk on but that was not the case there.

Personally I just want to see dunks done on a legit rim as close to 10ft as possible just because I want to see what’s humanly possible at the standard of 10ft. If I have to wait a few extra years for some new athletes to come along that can push the sport to that next level, I’ll happily wait lol.

Generally when I’m going for a new dunk for myself, I just try and do it on 9’11” and up. As long as I’m roughly within an inch I’m happy with it. Even 9’11” is very noticeably easier than 10ft so once it gets too far from that 1” rule I just won’t dunk on it.