4 pinkies probably means he should be on at least fuzzies by this point. Pinkies don't have a tons of nutrition,l something a little older will give more calcium.

A yearling is a bit young for a male to go off feed. They don't tend to be aggressive, just very active and not willing to eat.

For aggressiveness that's not typical or a corn. I would triple check temperatures, nothing makes a snake cranky like being too hot.