T9s

Yea it really smells like a set but you block those quite well. Some guys will go crazy with overpairs. I think it is not impossible for him to have something like QcJc either.

What is your plan when you just call a flop 3bet? I'm not sure if it is good to just call there and plan to fold on any turn that completes draws. And what if it is a blank, how much money is going in anyway? I think I would just shove OTF and hope he shows AA. If you just call OTF, I think you should just call it down on later streets. I see no point in calling flop and then raise shoving turn.

If he has you beat, there's little magical you an do abut it. All goes in. But if you are winning, plying this way might ensure the whole stack, the big problem being possible counterfeit on the river (like here).

You will be facing sets, combo draws.
I think we can play for stacks here.

Pretty tough spot but I think it's still fine.

UTG raises to 3,5bb preflop. That's something good regs probably won't do at this limit. If he is not a good reg, I would expect him to 3bet all overpairs OTF and maybe even AT sometimes. There are also stuff as suited broadways with flushdraws, I would expect him to have this from time to time. All that combined, with the fact that we block TT and 99, I would just try to stack off OTF.