Delete administration on iPad?

Hello,

We have an iPad from school that was connected to the school administration so that we could access everything from the school and not download any apps. Since this annoyed us all, we simply deleted the administration and created a new Apple ID (with our school email address). Now we're leaving school, however, the administrator wants to reset the iPad. But does he still have access to the iPad if the administration, i.e., the connection, no longer exists?
Also, our school email is being deleted. Will the Apple ID still work?
Thank you in advance, LG