You can never tell. If he wants to be with you, he'll stay. Otherwise, he'll just bugger off.
I suggest you keep him in for a few days, give him lots of fuss and lots of treats (prawns, tuna etc etc!!), make him really happy. Open windows a bit (not enough that he can get thru, so that he can get a smell of the area, then maybe put him in a cat basket and sit with him outside for a bit - feeding him ham thru the bars!
Basically, suck up to him in a big way and make him really want to live with you! Then you are just going to have to take a chance. You can't lock him up for ever.
It's what I did for both of my moves, and my 2 are still with me! - during my 2nd move of over 100 miles they soiled themselves so bad I had to put their cage in the bath and turn the shower on them. Then let them out, they went tearing round the bathroom giving me all kinds of verbal abuse! I made me peace offerings (Prawns and wafer thin ham) and towelled them down, then let them sniff round the house. Next day, I let them out. No problems.
The secret is to REALLY suck up!!!!!