This year, our filly is the way "little Devil" is. I don't think it's just gender related.
Sounds like you have a good handle on what you are doing. Does he have a lot of whiskers? Our babies this year have really long ones. If you get time w/o "jumping on" your little dude, when he bites at you grab whiskers and just kinda hold them or pull. Try not to hit him or yank - but it works wonders. Another way is to have him "run into" body parts. For big horse foal and some of the larger ponies, an elbow works well. Otherwise, your knee? He looks sooo tiny...
Can you kick him back - preferably just like a horse would? (with your "butt" to him and kicking backwards). You do have to connect at least the first couple of times for it to mean something to him. After that, just threatening may/should work... Though it sounds like he will keep trying. Honestly, it's harder for me to do that now than 15 years ago - but it works.
Other than that, I've just been very watchful (sometimes that's sooo trying, LOL). As he aims, pushing his butt away from you shoves him off balance and they get tired of it after a while...