I think there is very little value in betting here. You have to be good around 35% of time, since you're risking 1BB to win 2BB, to warrant betting. I doubt this is the case.

I'm having trouble assigning both players calling hands, which we're beating. In my opinion, UTG alone is ahead a significant amount of the time when he calls. Here are my thoughts on his hand combos:

UTG possible holdings
Hands we're ahead of that call:
99 6 combos
TT 6 combos
Total: 12 combos

Hands we're behind that call/raise
AA 3 combos
AK 12 combos
AQ 12 combos
AJs 2 combos
QQ 6 combos
KK 6 combos
Total: 41 combos

I also think TT and 99 can be discounted a bit, (as can AA, KK and QQ) as he'd likely bet/raise the flop with these holdings. Therefore, against UTG alone we are behind ~75% of the time. Throw in MP and I'm quite confident a bet here is -EV. I know of very few players that will call with K-high, etc. and thus did not take this into account.

EDIT: It's argueable that UTG may bet with a pair of As on the river, and thus the A pair combos should be discounted quite heavily. Though I believe it is highly probable he check/calls these hands given our passive read and the scary board.