No, it isn't totally necessary to neuter a male. If it is convinient depends on the individual character. At 3.5 months there's still a lot of growing up ahead.
My free range house bunnys are an intact 10lbs buck and his spayed girl. He has the better litter habits, although at some times there is some spraying to mop up, but normally he tries to discolour his cuddlebun when they are outside.
I have to say that I took him in when he was already 2yo, in his first year he did a lot of spraying, a happy horny juvenile, pee was dripping from the roof of his hutch at times, but well, every rabbit is different.
I know, and like him the way he is. And since I live alone in my own house there's a lot of leeway about what is still acceptable
No aggressions whatsoever. Different to does there is no relevant cancer risk with males (and the numbers for uterine cancer repeated over and over are imho vastly exaggerated as a deadbeat argument, nothing close to them, more like 20%-30% with abnormalties in their lifetime, but, among a lot of others that too is still a valid argument for spaying).
There are those benefits, mostly not getting offspring, and when he gets the spring fever my boy can be a PITA for his cuddlebun, thank god she just shrugs it off. He his much more active than her though (good thing), can't feed them same amounts because her legs wouldn't reach the floor by now.
