I did some very amateur analysis on that Youtube video. Here are a few frames:
Yes, the puck is incoming in first frame, very near impact in the second (can't even see it), and rebounding in the third and fourth. I think it's pretty clear from the third and fourth frame (and also the sound in the original video) that the puck hit his helmet. If it had hit him in the jaw in that position it would not have bounced up like it did, and it's far more likely that Zucc would have had a very visibly apparent injury after the fact.
I don't know how to feel about this regardless. Player helmets are not designed to withstand direct impacts from big slappers. Hopefully he checks out OK and has avoided a concussion - scary stuff for sure.