teachers group
In the Admin Panel you can specify who can create classes - see how here If you want to restrict classroom creation to just verified teachers you need to maintain the verified teachers group.
Classroom manager will allow you to manage that group
To list members of the group
Classroom Manager will create a sheet called ClssRmTchrs
Select Classroom Manager>Admin Menu from the add-ons menu. That will open the sidebar
Select Domain Admin
Click on List members - that will populate the ClssRmTchrs page - Layout shown below
Adding new teachers
To add new teachers enter the email addresses in Column K
Once you have added all the records click on Add Members in the sidebar menu
When the new records are added a message will appear in column H for each record added
Removing teachers
To remove a teacher enter a Y in column H against the relevant record(s)
Then click on the remove members button in the sidebar
A message will appear in column H