Is that the end of the hand history?
seems like a very easy call given pot odds and try to spike on the river.
I don't mind your turn bet too much. Both checking and betting has merits to it. Since you didn't give any reads on the BB hard to tell you which is better.
If you think he folds 2nd pair on the turn then betting K7 for value is way too thin and you should check but if he calls 9x and all draws every time then it's not too thin and you should definitely bet.