Hi,
Best way to play it: fold preflop. K9o is junk, especially out of position, there is no way the "cheap odds" you get warrant playing that hand against an unknown.
I don't mind the raise the flop, who knows what that guy is doing and our top pair could very well be good until proven otherwise. However, bad players rarely minbet/min3bet without a very strong hand, they'll minbet/call or minbet/fold most of the time with marginal stuff. Occasionally you'll catch aggro donks doing that with whatever air hand they have as a rebluff because that's just what they do. So from this point on I'd just be bluff-catching and folding as soon as it gets too expensive barring a read that he's really bluffy.
Hope it helps.