100NL - Bluff the river?

[kitaristi0]

I found this hand from maybe a month or two ago while going through my PT database today. I don't know anything about the villain. Do you think bluffing the river is profitable here?

I don't think he folds a 9 to a river bet though it's possible, but does he have a 7x, small/mid-PP or random flop float with an A-high type hand enough to make a bluff +EV? Does your answer change if the flop was 9[img]/images/graemlins/spade.gif[/img], 7[img]/images/graemlins/club.gif[/img], 2[img]/images/graemlins/spade.gif[/img]?

PokerStars No-Limit Hold'em, $1.00 BB (4 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

BB ($110.20)
UTG ($228.05)
Hero ($105.50)
SB ($217.55)

Preflop: Hero is Button with J[img]/images/graemlins/diamond.gif[/img], K[img]/images/graemlins/diamond.gif[/img].
<font color="#666666">1 fold</font>, <font color="#CC3333">Hero raises to $4</font>, SB calls $3.50, <font color="#666666">1 fold</font>.

Flop: ($9) 9[img]/images/graemlins/heart.gif[/img], 7[img]/images/graemlins/club.gif[/img], 2[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
SB checks, <font color="#CC3333">Hero bets $6</font>, SB calls $6.

Turn: ($21) 2[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
SB checks, Hero checks.

River: ($21) Q[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
SB checks, Hero ?