[Antinome]

Once he's donked into me the second time I'm sure he's still on a draw. We already know he donk-calls from the flop action. Why wouldn't I want him to call me with the draw? My equity is better than it was on the flop.

Now a flop flat call, that's not bad if we're heads-up. I'm probably slightly ahead, I can call and keep the pot small... re-evaluate turn, raising if he donks again, when my equity is better. That would be my normal line. But I'm worried that if I flat call an obvious donk draw BB will raise with a wide range and I'll be unable to call. Even if he's not raising, he may still call with a wide range. I really don't have good equity against a draw and another hand. The flop raise is more to isolate than get value from the probable UTG draw, though it serves that purpose too.

I don't see why the 9 is a bad card; it only completes one (reasonable) draw, KQ. Most UTG posters will raise a hand like that. If anything, I suspect even before he donks turn that it just made him a pair to go with a straight draw, or missed his flush draw.