Sometimes, depending on the size of the package or bag, CMs will watch your things on the platform or hold it by the podium while you ride. YMMV with this. If you have the time after your shopping and before heading for IC, there are lockers by the entrance on BVS where you can store your things for the day -- then you wouldn't have to worry about them while riding any ride and you could add more things to the locker throughout the day, too.