Not slow playing... but playing slowly

Party Poker Pot-Limit Hold'em, $ BB (6 max, 6 handed) FTR converter on zerodivide.cx

BB ($31.05)
UTG ($44.20)
Hero ($39.80)
CO ($8.55)
Button ($59.80)
SB ($32)

Preflop: Hero is MP with A[img]/images/graemlins/diamond.gif[/img], T[img]/images/graemlins/spade.gif[/img]. SB posts a blind of $0.25.
UTG calls $0.50, Hero calls $0.50, <font color="#666666">1 fold</font>, Button calls $0.50, <font color="#CC3333">SB (poster) raises to $0.75</font>, <font color="#666666">1 fold</font>, UTG calls $0.50, Hero calls $0.50, Button calls $0.50.

Flop: ($4.50) 9[img]/images/graemlins/spade.gif[/img], 2[img]/images/graemlins/diamond.gif[/img], T[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(4 players)</font>
<font color="#CC3333">SB bets $1.5</font>, UTG folds, Hero calls $1.50, Button folds.

Turn: ($7.50) 7[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">SB bets $3</font>, Hero calls $3.

River: ($13.50) 6[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
SB checks, <font color="#CC3333">Hero bets $4</font>



I think most would raise this 6 handed; I did not hear. My style is a little looser and more passive preflop than I think most here. This is certainly up for debate.

On the flop the min raiser has at most a pair almost all the time. I sincerely doubt an overpair. The board is relatively drawless, so I don't mind keeping the pot small.

The turn picks up more draws, should I raise here?

I felt his most likely holding on the river was a weak pair which would have trouble folding to such a small bet. He would have to fear the straight and would not be able to value raise me; this is an easy fold to anything but a min check raise.

Thoughts?