2 pair vs. 2 loose opponents

[atrifix]

MP1 is LAG. Button seems loose-passive but I'm not really sure yet.

Party Poker 0.50/1 Hold'em (9 handed) converter

Preflop: Hero is BB with 4[img]/images/graemlins/club.gif[/img], 9[img]/images/graemlins/heart.gif[/img]. CO posts a blind of $0.50.
UTG folds, UTG+1 folds, MP1 calls, MP2 folds, MP3 folds, CO (poster) checks, Button calls, SB completes, Hero checks.

Flop: (5 SB) 4[img]/images/graemlins/diamond.gif[/img], 3[img]/images/graemlins/heart.gif[/img], 9[img]/images/graemlins/diamond.gif[/img] <font color="blue">(5 players)</font>
SB checks, <font color="CC3333">Hero bets</font>, <font color="CC3333">MP1 raises</font>, CO folds, Button calls, SB folds, <font color="CC3333">Hero 3-bets</font>, <font color="CC3333">MP1 caps</font>, Button calls, Hero calls.

Turn: (8.50 BB) K[img]/images/graemlins/spade.gif[/img] <font color="blue">(3 players)</font>
<font color="CC3333">Hero bets</font>, <font color="CC3333">MP1 raises</font>, <font color="CC3333">Button 3-bets</font>, Hero calls, MP1 calls.

River: (17.50 BB) A[img]/images/graemlins/club.gif[/img] <font color="blue">(3 players)</font>
Hero checks, <font color="CC3333">MP1 bets</font>, Button calls, Hero calls.

Final Pot: 20.50 BB

I felt fairly certain I had MP1 beat, but should I have mucked this when Button woke up on the turn?