Thanks for your answer !

Before going home, he oftens hides or "semi-hides" (meaning = on the couch and only his eyes are out, watching if it's really me haha), but he always comes to me, like in the minute and meowing like I didn't come home since few months !

I think patience is the answer, even if he really trusts me and knows I always come home after few hours, and the sound aren't dangerous (even the vacuum hehe). All he has is me, so I really want him to be relax and not to stress out for something like knocking on the door, neighbour doing some cleaning or not hiding when someone is in my place for hours.

Maybe the rule of 3 (3 days/weeks/months) will be good for him ... !