K9s in the BB

[JP2k1]

Given that you know your opponent is loose, it would seem that there would be a wide range of hands which he could have and give you the action he did on the flop and turn. He could conceivably have something like 9-6, or maybe even AX of diamonds and check-raised the turn when he picked up his flush draw. And if he's REALLY wild, he might even have something like AXo and decided to make a move when he paired his ace on the turn.

So, considering the wide range of hands he could have, I would assume your kings-up are probably best on the river. I'd have gone ahead and raised that river.