Nine square feet is pretty small for two boars, although at three months old, they should be ok in it for a little while longer.
I'd add another water bottle. What kind of hideys do you have? If they have only one door, take them out and replace them with something with two doors so no pig has anywhere it can get trapped. Upside down cardboard boxes (no lids, holes cut in both ends) will do. Or drape fleece across a couple of corners of the cage.
But the behavior you're describing is normal. They're trying to figure out who is top pig, and that may go on for months, even years. As long as they're not getting into all-out fights, I wouldn't worry about it.