At only 14 weeks he surely won't be adolescent yet!

People won't like this advice but - if he is going to be allowed out eventually - let him out. That way he can run around and use up all that energy that at the moment is going into being a monster. I sold a Burmese kitten once that was just like this, letting him out into the garden solved the problem instantly. I know people will think this is terribly young to be letting him out, but the alternative in this case could be dumping him on a rescue where the same thing will happen as soon as he is rehomed.

Liz