He can definitly have a 9, 77, 66 even T8. I dont know if he spazz jams TT or 88 here or if he shows you some rare JTcc type hand.

It's just so hard for us to be nutted here. What do we have here that can stand a raise? We MIGHT have J9 or T9 because its a 4handed table and we can resteal wider. If we don't have 99 then CO has everything against us and can do this all they want. Because of this I think GTO would say we need to pay off with some of these types of hands maybe? Because if we didn't then we just fold everything on turn. Against a guy who seems fishy, I think we fold here. I don't see too much of a bluffing range in this spot to pick off with QQ.

would be interesting to know what kind of aggression stats you have on him. In my experience whenever I have played against a "confirmed fish" and they show aggression I fold everything but the virtual nuts. I would likely c-bet the flop bigger, OTT I think checking back is a viable option as he could have T8,Ac7c, random overcards in clubs that he chooses to go with. would then likely fold to a river bet, because I do not think he would then turn a 7, underpair into a bluff, so you essentially have a bluff-catcher.

Due to your SPR OTF, I'd gone on 2 bets. Bet bigger OTF & push OTT. He has plenty of worse hands he can pay off with.