So it doesn't matter if you are a public school, charter school, or home school - or even if you just want to use it for Professional Development - you can use Classroom no matter who you are. Users will have the ability to join classes, and create their own classes.
GSuite for Education Admins will have the ability to exercise greater control over Classroom as a result of this update. If you are not a part of GSuite for Education, Google encourages you to join. You can find more information about GSuite for Education here.
In the meantime, if you are a personal Gmail user and you want to learn more about this powerful tool, watch these videos from my Google Classroom Playlist on YouTube!