55

i think its a bet on the river as played. looking at the bard and how he plays. i think it seems very weird to me that you decide to bet turn and not follow up on the river. I mean like the 6 yeah it gives you a gutter. but i dont find it a great card. so i think either you check turn and go passive perhaps a call down or fold river. or you bet turn and river. it feels like those two lines are the only ones that makes sense.

I would expect BB to checkraise most of his stronger pairs on the flop. It even wouldn't be bad for him if he checkraised something like A2 but I don't know if he would play a weak pair strong.

The bet on the turn is good because the majority of the range of BB will consist of an unimproved ace.

The risk should be pretty small that the opponent has a stronger hand on the river. There were no reasonable draws with a 9:c on the turn. A flush draw on the turn can't hit the 9:c on the river. A9 could beat you on the river but not much more. I would bet your pocket for value against an ace which could try to catch a bluff and against the weak pairs BB might not have raised on the flop.

BB might have some aces in his range on the river because he has still some equity on the turn. Also the risk of a bluff checkraise is very small. Any hand left in the range of BB should have some showdown value, so the motivation for a bluff is small.