How is asking him why he wasn't wearing a seatbelt berating him? It was clearly an opportunity for Hill to state he had taken it off to retrieve his identification or provide an excuse but Hill was too slow to pickup on that.
If the driver prevents the officer from completing the stop or endangers the officer, the officer has legal authority to use force. Hill blocked interaction with the officer and prevented the officer from seeing activity in the vehicle by rolling up his window.
We'll see. There's obviously subjectivity on these matters but I think it's pretty clear Hill overplayed his hand. As DaveXA indicates, the event is likely a nothingburger if Hill just cracked his window.