An AK hand

[Navers]

This is a 3-handed live limit tournament. We started out with T450 and the stakes are 20/40. The person I'm going to be up against is fairly loose and thinks limit poker is stupid poker and just keeps raising for fun.

I'm in the BB with AKo
Dealer calls, SB raises, I reraise, Dealer folds, SB calls.

Flop: 6 8 9 rainbow (2 players)
SB bets, I raise, SB calls

Turn: 4
SB checks, I check [img]/images/graemlins/blush.gif[/img]

River: J
SB bets, I call

I wasn't sure whether to bet the turn in case he had anything, maybe that was a stupid mistake. How was my play on the other streets?