How long should I wait to text him??

I'm neighbors with a childhood friends grandparents. His mom used to babysit mine and our family's go way back to before we were born. I've always been attracted to him, but was too shy to say anything and our family's would always be around. I saw him tonight briefly since he was at his grandparents and we talked for a bit but he travels a lot and just came home tonight. He is back home for a couple of weeks and I'd like to catch up with him because we never get to see each other anymore. How long should I wait before I message him and say "it was good seeing you the other night"? I'm not looking for a relationship out of this just maybe a little fun while he's home.