Misplayed in the BB

[StableHand]

PokerStars No-Limit Hold'em, $4 BB (9 handed) converter

MP1 ($670.95)
MP2 ($396)
MP3 ($80)
CO ($641.30)
Button ($188)
SB ($392.20)
Hero ($474.05)
UTG ($631.50)
UTG+1 ($286.20)

Preflop: Hero is BB with 6[img]/images/graemlins/diamond.gif[/img], 4[img]/images/graemlins/diamond.gif[/img]. CO posts a blind of $6.
UTG calls $4, <font color="#666666">4 folds</font>, <font color="#CC3333">CO (poster) raises to $12</font>, <font color="#666666">2 folds</font>, Hero calls $8, UTG folds.

Flop: ($32) 7[img]/images/graemlins/heart.gif[/img], 5[img]/images/graemlins/club.gif[/img], 5[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, <font color="#CC3333">CO bets $20</font>, Hero calls $20.

Turn: ($72) 8[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, CO checks.

River: ($72) 9[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $80</font>, CO folds.

Final Pot: $152

Results in white below: <font color="#FFFFFF">
Hero has 6d 4d (straight, nine high).
Outcome: Hero wins $152. </font>

Unfortunately I wasn't paying much attention to this hand until it was just finished, but I think the right way to play it would have been to lead out on the turn, call a raise, and check-call / check-raise the river, depending on what card falls. As I failed to bet the turn, I should have made a $30-40 bet on the river. Is that pretty OK?

[SeattleJake]

newbie response:

I don't like the pre-flop or post-flop calls. Once you hit on the turn though, I would have bet for value. After getting the short end of the straight on the river, I'd have check-called or bet half-pot there.