Most Helpful Guy
He's not sexually mature yet, so it's not a sexual behavior. It's actually a display of dominance. He's literally dominating his toys, perfectly normal behavior. As he gets a little older, he'll calm down. If he was still with his litter, they'd be establishing their dominance hierarchy right now, but since he's alone, and submissive to your family, he just wants to be able to boss someone around, so he's treating his toys like litter mates.