Seconding that you wait until he's eaten for you 3 times. This is to ensure he eats for you constistingly and that he's comfortable in his new enviroment, as well as making sure your husbandry is on point.
Him eating for a month at Petsmart is not the same as him eating for you. He's in a whole new world now and he NEEDS time to acclimate in his new set up. You need to be patient with little beeps, any change can make them feel unsettled enough to not eat.
Especially if he was underfed at Petsmart he MAY eat for the first one or two times, but this isn't a good indication he's comfortable or fully settled. A third helps make sure he's eating because he's feeling secure enough in his new home rather than feeling starved.
Hes going to be with your for many years, so don't worry a few weeks is nothing :p Remember you're doing this for him.