Ahhhh that's a relief - for him too!
Whenever a new kitten goes to a new home I always give the new owners a bit of wee-soaked litter. Or if getting a new kitten I ask for some....
Yep they look at me funny...
yep it smells a little...
but mix that into the new tray and the kitten will automatically feel at home.
How would you feel if you went somewhere new and had no idea where the loo was, and couldn't ask?
Glad he's happy... for now just leave a tiny bit of smelly used to remind him, every time you change the tray, and if you give him another tray somewhere else do the same, put in a bit of used litter - they rely on their scent to guide them.
You're unlikely to have accidents if you remember to put up a sign saying "Kitty Bathroom" in cat language, by just adding a little of his own used litter to wherever you want him to go. It doesn't have to be much as they have much better noses than us....
Also remember that a new kitten exploring can get overwhelmed and forget where to go or get lost, so a few small trays in every room to start with helps... if there's some scent in it to start with, he won't miss.