You can, of course, create a verb охуить, but I do not think that it exists in “normal” Russian speech. The adjective охуительный is formed from the verb охуеть and the fact that a vowel has changed is completely normal for Russian (compare зреть и зримый).
As I said, охуить is not usually used on its own, and its meaning is only relevant when you derive things from it. And it is a transitive verb.
Also, this thread gives me giggles.
You can, of course, create a verb охуить, but I do not think that it exists in “normal” Russian speech. The adjective охуительный is formed from the verb охуеть and the fact that a vowel has changed is completely normal for Russian (compare зреть и зримый).