Preflop bluff turns into money by the river

[ZootMurph]

MP2 is a LAG preflop(47%/31%), but very rarely shows down hands, either folding after the turn with nothing or jamming the pot. Button is a classic calling station. NEVER raises, just calls. He only bets with a big hand when checked to, otherwise you can be sure he will call with something and fold with nothing. My image has to be weak tight at this point, as I've been getting absolutely nothing for the last hour, and I've tried to play a couple of weak hands in position and had to fold most of the time postflop. The last hand I showed down was AA vs K9s that rivered the flush and didn't even bet the river OOP.

Party Poker 2/4 Hold'em (9 handed) FTR converter on zerodivide.cx

Preflop: ZootMurph is MP3 with 7[img]/images/graemlins/heart.gif[/img], 6[img]/images/graemlins/heart.gif[/img].
<font color="#666666">3 folds</font>, <font color="#CC3333">MP2 raises</font>, <font color="#CC3333">ZootMurph 3-bets</font>, <font color="#666666">1 fold</font>, Button calls, <font color="#666666">2 folds</font>, MP2 calls.

<font color="Green">Preflop, I'm basically trying to get heads up against the LAG, and hoping he doesn't hit his hand so I can push him off. Unfortunately, button comes along for the ride. </font>

Flop: (10.50 SB) 5[img]/images/graemlins/diamond.gif[/img], K[img]/images/graemlins/spade.gif[/img], T[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(3 players)</font>
MP2 checks, <font color="#CC3333">ZootMurph bets</font>, Button calls, MP2 folds.

<font color="Green">Obviously, I don't like this flop but I decide to follow my initial plan and see what happens. So I bet and, as expected, LAG folds. Unfortunately, Button has something and calls. I tell myself I'm done with the hand. </font>

Turn: (6.25 BB) 4[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">ZootMurph bets</font>, Button calls.

<font color="green">OK, I now have a OESD. If I don't bet, Button will. And I will call. So, I decide betting is better than check/calling. </font>

River: (8.25 BB) 8[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">ZootMurph bets</font>, Button calls.

<font color="green">What a beautiful runner runner straight. Lucky me. I bet, mainly because I'm not 100% sure of the bet from Button to check raise, with the flush draw coming through on the river.</font>

Final Pot: 10.25 BB

Any thoughts on this play?