Unfortunately, using the myCricket app to view all your kids’ usage is not recommended. Cricket Wireless wants its service to be as affordable as possible, and so they opted not to store data like call logs and messages on every subscriber’s myCricket account as it’s quite expensive to update from time to time.
So, the only way you can get an update on your kids’ Cricket smartphone is through the ways presented above. But do take note that Cricket’s response may get delayed at times.