The primary definition of whack is to hit something. That is common and not vulgar. The player whacked the ball right out of the park — the baseball player hit the ball right out of the park. The way you put it is slang and would likely be considered rude. I have not heard it as “are you hurt”. Instead it is: Are you crazy? Are you on drugs? Something is not right with the person. Sometimes it can mean someone is ugly - like they’ve been hit in the face.

Petty much., but it's used more to describe your own condition rather than another person. E.g "I've worked 15 hours today, I'm complete whacked"

In New Zealand, whacked is an informal way to say very tired or exhausted.

I always understood that phrase to insinuate 'drunk'. Someone drank too much, "That guys is wacked".