I don't really mind the smallish flop bet on that board. It's fairly dry and i'm not sure what worse hands are calling a big bet. As a matter of fact if he is particularly aggro i may even check my kings on the flop and hope he bets into me. My aggro i means he will bet a lot of air and draws and hands that we beat if we check. If you decide to play you kings as a bluff catcher i think you need to continue the facade on the turn as well. Then if he bets again on the turn probably call depending on his double value betting range. Some folks are plenty brave on the flop but will not fire a second bullet unless they have a strong hand. Also like the turn bet i would bet fold the river. I doubt he is raising with anything that we beat. If he is really passive post flop. Thats to say he's never betting without and ace or better i may even check the river. Then i can confidently fold when he bets and not worry about being bluffed.