KK When an Ace hits the Turn

First of all you should always try to make sure have at least 100bb at the table.

I would probably 3bet a little bigger pre, 0.42-0.45, do you have any stats for his fold to 3bet% or fold to cbet%?

I see no reason not to bet the turn, he doesn't have to hold an A here, could easily have a smaller pair. I also think we have more Ax in our 3betting range then in villain's calling 3bet range.