You will notice the general temperament with ball pythons is just that, laid back or chill to the point of plain lazy like a cat. And hide much more than choose to bite
the head bob is something they do when sticking their heavy head up to parascope and look around it will probably go away as he bulks up his muscles but there is also a gene that causes the head wobble in a morph of ball python called spider. Did you perhaps buy a spider ball python? Then the wobbles are part of the snake but if it doesn't effect his eating its generally excepted as just fine and some go as far as thinking it's cute.