My friend used my scratch account without my permission and made an inappropriate account with a bad username and it says “This account was blocked because it was used to go around a block on another account” I've been banned for 9 months now and I need the account back (The username is “___—-__–l_L__” ) Anyone know how to get unblocked or do a ban appeal?

Appeal here: https://scratch.mit.edu/contact-us/
Ensure you’re kind about it.

Email Appeals@scratch.mit.edu. More likely to be seen than contact us in my opinion, at least for bans. Ask nicely and they might let you be unbanned.

Since your block is related to a case of account sign-up information having been shared, it would be difficult to resolve the appeal without an adult confirming which account belong to which person. Your best best is to ask a parent (or teacher if you use Scratch for school) to contact the Scratch Team so they can talk with the Scratch Team about their plans to make the account and e-mail used for sign-up single-user only.