Humping and chasing isn’t being aggressive, it’s part of the dominance behaviour.
your boys have now started the teenage phase. This goes on from 4 to 14 months, with a few hormone surges occurring during that time (the first being at seven months of age).
Piggies are ground roaming animals so I’m afraid that additional floors don’t count towards ‘space’. How big I the bottom floor of their cage? Boys need at least 150 x 60cm on one level. If your cage is less than that (one level), then you need to find a way to make it bigger. Either by linking another cage to it, buying a bigger one, or setting up a playpen to which they have 24/7 access. Space is very important when it comes to boars.
Also make sure that you have two of everything - hides, bowls etc.
PS does the one with the torn ear squeak when the other is chasing/humping him?