Kitty baby is too cute for words
The only cat my family ever bought (we've mostly taken in strays) came from this kind of dingy pet section in a back corner of a not-so-super supermarket. The sign on the kitten cage even said they were too young, to anyone that could do basic math--it gave their birth date, seven weeks ago. At that age they should have been bouncy, but they had no space to run around. We bought one on the spot--it was practically a rescue operation. So I totally understand why you bought this little cutie early to get him out of those conditions. Two more weeks of that
would NOT have been better for him than two weeks with you.