BB flop check/raise

[New001]

Dropped down to 5/10 while I transfer my BR around.

Everyone in here is somewhat unknown, and this is just my 2nd or 3rd orbit. Button is tightish preflop so far, others are loose passives.

Party Poker 5/10 Hold'em (6 max, 6 handed) internettexasholdem.com

Preflop: Hero is BB with 9[img]/images/graemlins/spade.gif[/img], Q[img]/images/graemlins/diamond.gif[/img].
<font color="#666666">1 fold</font>, MP calls, CO calls, Button calls, <font color="#666666">1 fold</font>, Hero checks.

Flop: (4.40 SB) 4[img]/images/graemlins/diamond.gif[/img], 9[img]/images/graemlins/club.gif[/img], A[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(4 players)</font>
Hero checks, MP checks, CO checks, <font color="#CC3333">Button bets</font>, <font color="#CC3333">Hero raises</font>.

I haven't run into one of these in a while. Is this better than betting out or calling or folding?