Pocket pair with trips on board

[fryKing]

MP3 is a complete and total manaic, although he is an unusual one - he plays 80% of hands, never raises before the flop, but always bets and raises the flop and turn. He capped the flop and turn with a J6s flush draw and no other outs, for example.

No read on the other player.

Party Poker 2/4 Hold'em (9 handed) converter (http://www.selachian.com/tools/bisonconverter/hhconverter.cgi)

Preflop: Hero is UTG with T/images/graemlins/spade.gif, T/images/graemlins/club.gif.
<font color="CC3333">Hero raises</font>, UTG+1 folds, MP1 folds, MP2 folds, MP3 <font color="purple">(maniac)</font> calls, CO folds, Button folds, SB folds, BB calls.

Flop: (6.50 SB) 9/images/graemlins/spade.gif, 9/images/graemlins/club.gif, 9/images/graemlins/heart.gif <font color="blue">(3 players)</font>
BB checks, <font color="CC3333">Hero bets</font>, <font color="CC3333">maniac raises</font>, <font color="CC3333">BB 3-bets</font>, Hero calls, maniac calls.

Turn: (7.75 BB) A/images/graemlins/spade.gif <font color="blue">(3 players)</font>
BB checks, Hero checks, <font color="CC3333">maniac bets</font>, BB calls, Hero calls.

River: (10.75 BB) 5/images/graemlins/heart.gif <font color="blue">(3 players)</font>
BB checks, Hero checks, <font color="CC3333">maniac bets</font>, BB calls, Hero calls.

Final Pot: 13.75 BB
<font color="#990066">Main Pot: 13.75 BB, between maniac, BB and Hero.</font>

While maniac clearly COULD have the case 9 there's no reason to assume he does just because he's betting and raising. BB clearly doesn't have a 9 as he got scared.

thoughts on how I played it? What are the other player's hands?

[AceHigh]

You played it fine. Only thing different is I would check/raise the river.

FWIW, if there was a decent chance the Big Blind had a better hand, like KK/QQ/JJ, I would bet the turn and hope the maniac drives him out with a raise. I don't think it's likely the BB has a better hand unless he has an 9 and he's not folding that, and it's unlikely for reasons you stated.