With the 12.0 iOS update, Apple has enhanced parental restrictions. Parents could limit apps and websites their child accessed. Now parents can also limit when the child can use the device. Apple Support describes how these new features work: Downtime, App Limits, Always Allowed and Content & Privacy Restrictions.
How to Start Using Screentime
Hands-On Parental Controls in iOS 12
Using Find my iphone
This tutorial shows you how to locate a lost iPad or iPhone. If the school iPad is unable to be located, contact a librarian for next steps in the lost iPad process.