YEAH!!! I’m so happy to hear he is learning to use the litter box! 
Hopefully he will keep getting an A+ on litter use and not have any more accidents. I would give him a box in the living room (maybe with a pinch of his old litter in it) and let him be in there with supervision. I would show him the box first then let him play in the living room. Also food/treats are a irresistible way to get kittens back in their room.
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