Bottom set, 3 to the straight, 2, to the flush, unraised pot

[Beanos]

Party Poker
No Limit Holdem Ring game
Blinds: $0.50/$1
5 players
Converter

Pre-flop: (5 players) Hero is SB with 6[img]/images/graemlins/spade.gif[/img] 6[img]/images/graemlins/diamond.gif[/img]
UTG calls, CO calls, Button calls, Hero calls, BB checks.

Flop: 7[img]/images/graemlins/heart.gif[/img] 6[img]/images/graemlins/heart.gif[/img] 9[img]/images/graemlins/club.gif[/img] ($5, 5 players)
<font color="#cc0000">Hero bets $4</font>, BB folds, UTG calls, CO folds, Button calls.

Turn: Q[img]/images/graemlins/diamond.gif[/img] ($17, 3 players)
<font color="#cc0000">Hero bets $14</font>, UTG calls, <font color="#cc0000">Button raises to $54</font>

Vill is 19/14/4, seems ok. I thought he would raise the flop with the straight (unless he has the straight and flush draw). Would he play a bigger set like this, waiting for a safe turn?