PLO8 $2: Flopped boat, scary river

[Heron]

Sorry for the low limit but I'm a miser and I'm still learning. The hand is simple and played itself but I'm not sure about what's the right play on the river.

I sit in the BB with K976 rainbow, 5 limpers, SB folds

Flop: KK9 (rainbow, one spade)

I bet the pot and get one caller.

Turn: 5s

I bet the pot and get called again.

River: As

My stack is approximately twice the pot, my opponent's stack is a little bit smaller (1.5 pot).

Knowing that many at this level will find it difficult to fold an underfull, a flush or even trips, initially I wanted to bet the pot again, but then I opted for a check / call instead, for following reasons:

1. I save half of my stack when I'm beat. It's quite possible that the A made him a better full house. To call my flop bet in his shoes I would need a K and at least two bycards bigger than 9, but then I would fold the turn unimproved. The typical player at this level is more optimistic though.

2. I might be bet into by a losing hand.

Well, when my opponent checked behind and mucked his loser I felt like a fool, but this morning while riding to work by train I liked my line. Now, again I'm not so sure. What do you guys think?