I'm in a tough spot on the turn in this hand. UTG is a maniac, BTN is fairly new to the table, so I have no solid reads on him. Maniac will push in with top pair on the turn or river (but those were pots with bigger top pairs). I underbet the flop a bit (mental error). Looks like maniac is blocking the turn on a draw, but I'm worried as to what BTN has to cold call two bets. Any decent raise should probably be a push (I think). What's the best approach in this type of situation?

Hero ($48.50)
CO ($62.50)
Button ($97.75)
SB ($36.10)
BB ($38.80)
UTG ($69.40)

Preflop: Hero is MP with J, J.
UTG calls $0.50, Hero raises to $2.5, 1 fold, Button calls $2.50, 2 folds, UTG calls $2.

Flop: ($8.25) 3, 5, 6 (3 players)
UTG bets $3, Hero raises to $12, Button calls $12, UTG calls $9.

Turn: ($44.25) A (3 players)
UTG bets $0.5, Hero...