He looks so sweet! What have you named him?
I remember getting my rabbit for the first time, he was a little older than yours but he had a problem with going to the toilet everywhere for a while then it wasn't so much. He's been done but we've never really had a problem since he settled down here. It may also be nerves, I'd imagine he'll be scared for a while.
But getting him neutured would be the best thing to do in the long run for many reasons.