I think he needs to be nuetered for one thing, I know he is probly to young, but this will help solve alot of your problems.

For another thing the litter box may not be big enough for him. Jaxom has a litter pan that he could stretch out in and pee/poop in without going over the edge but he always did.

A way that I check is the litter pan 2 inches longer then him? If not then it's time for a new litter pan. Also, one with taller side would probly help.

Ashley