Wow 7 MONTHS old? That snake looks tiny! Where did you buy him?
I would make sure to leave him alone for at least two weeks. No cleaning or feeding attemps are needed during this time. Just leave him be. As for sub adult, I can't really say, I just know mine are teenagers when they aren't babies anymore, but not as big as adults. LOL
By the looks of your snake, he looks more like a newborn than a subadult though. But it could just be the photo
Marisa