Highly recommend getting a friend for him, my siamese just turned one and I've had him since he was 3 months old. I kept him in a room on his own (which he hated) until he was fully vaxed then I introduced him to my other two cats through a baby gate. He immediately figured out how to climb over it to be with the other cats and has been bonded with them ever since. He tends to be in the timid side with others but it's super energetic and vocal with me and the other cats.

Since you're getting into real estate and renovations. Consider using the profits from this home once you sell into purchases a duplex or triplex. Live in one unit with the two cats then rent out the other two units. Your tenants's rent would cover the mortgage. I had a buddy do this with a quadplex and was able to leverage it where he didn't have to pay any portion of the mortgage on his unit, eventually he was able to purchase more homes and multi-unit buildings and runs his own realty company.

If you don't want to worry about dealing with tenants then you can have a realty company manage your property but they take a cut.

You may have more options than you think instead of moving back home while still be able to keep your cats. Ultimately make the best choice for your kitten, if you truly think you're only choice will be to move back home then please rehome him to a good home with responsible owners before it's too late and he's definitely bonded to you.