Spewing or calculated aggression?

[J. Stew]

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

Preflop: Hero is SB with 7[img]/images/graemlins/heart.gif[/img], T[img]/images/graemlins/heart.gif[/img]. CO posts a blind of $0.50.
<font color="#666666">5 folds</font>, CO (poster) checks, <font color="#666666">1 fold</font>, Hero completes, BB checks.

Flop: (3 SB) 9[img]/images/graemlins/diamond.gif[/img], 8[img]/images/graemlins/spade.gif[/img], A[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(3 players)</font>
<font color="#CC3333">Hero bets</font>, BB folds, CO calls.

If I check the flop and CO bets, I don't have the odds to chase in this small pot. If I bet the flop there is a decent chance they will both fold (CO posted) and I've got outs of course.

Turn: (2.50 BB) K[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, CO calls.

There's two scary cards if he has a small/mid pair and I'm playing like I have some piece so there is a chance he peeled and will fold. He may be drawing too so I bet.

River: (4.50 BB) 4[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, CO . . . (I'm not telling)

The only way I can win this hand is to bluff at it. I'm HU and he has just called the whole way. If he had an Ace wouldn't he have raised the flop. If he caught a K on the turn fine. If he was drawing without the odds to a flush he didn't make it. Would he really call down with bottom pair on the flop?

Final Pot: 6.50 BB

I think I overplayed this hand, but the part I am confused about is that these situations, where you flop a draw in a shorthanded limped/checked pot, come up somewhat often and I find myself folding frequently or everytime to C/O's auto-bet when it's checked to him. Is this just the luxury that C/O has here with position and there is no move worth making in this spot? Or does anyone make a play here? Thanks. Look at my boobs.