Short stack goes all-in, I have A9s

[Mammux]

Small live multi-table tournament. 21 players, buy-in is $100. Starting stack 10k. We're down to 7 players. Blinds are 500/1000, plus 100 ante.

Stacks: UTG+1 12600, UTG+2 2400, UTG+3(me) 14000, CO 2800, button and big blind: 50k.

UTG folds, UTG+1 limps, UTG+2 goes all-in. I have A9s and call. CO goes all-in (the raise is too small to allow for reraises), fold around to UTG+1, who calls. I call as well.

The flop is TT9, suited but not my suit. UTG+1 bets 5k, he has 4800 left.

Of course, my call preflop was a serious mistake. Should I have bet (all-in?) or folded? Also, what do I do now? I have 11200 left in my stack, the pot is 10800 plus the 5000 he just bet.

-Magnus