maybe he's having bladder problems, and can't hold his pee properly.
I would suggest having him checked out.
If your cat every suddenly starts behaving different or extreme and you don't know why, make sure their health isn't the problem.
difference between spraying and pissing is that cats spray standing up while jerking their tail around.
cats squat while pissing.
also make sure his litter is very clean, clean it once a day even if it doesn't look very used...in fact if the vet says he's okay, start putting litter boxes strategically where he seems to be going.
One thing i can say is don't rub his nose in it, nothing is ever gained by rubbing an animals nose in it's own urine or feces.
main reasons I can think for this behavior is , no bladder control (health problem), territorial behavior (some animal in the area looking in your windows) or dirty litter box.
we've had this problem at my house and now there are litter boxes strategically placed in most rooms and doors to rooms that we aren't in are shut when we're not in them so they can't go in there. So far it's working really well.
If in the final case you need to get rid of him, please don't just kick his bellybutton out the door, give him to the vet or an adoption facility.
If you kick him out he'll probably get mangled by a dog, a car, another human or starve, or a combination of those things.