50 freezout on Strars, 10K prize fond. I am ITM with a healthy stack, I had about 27k, blinds were 800/1600 and 75 antes. (not sure exactly about antes.)
I am in position to the 2nd biggest stack in the tourney, he is very loose and bad, i.e. limps with marginal hands, calls AI as underdog, and hits.

(Several orbits before we played a hand : Shortstack in middle position went AI, he called OTB, I overpushed with TT from SB, BB folded, he folded and I won a nice pot against shorty, who had 44. )

Now the hand:
Preflop: Short UTG (8500) pushes, Big stack (66K) calls in MP, I am next to act with and think about pushing.

What do you think? Other players on the table are quite tight and wouldn't come in the pot without QQ+, AK. If I let this opportunity pass I still have good chances in the tournament, asmy stack is bigger than average.

I'd probably pass. Like you said, you have a healthy stack at a tight table. This gives you a ton of chances to steal blinds and increase your stack without risk. And if you get re-raised you'll have enough to fold and still be ok. I'm sure you'll find a better spot to push against the big stack than with AJ.