To be able to update Home and Playground apps on an Android device, you will need to have a Google account. If you already have a Gmail account, then you are good to go. If you don't have one yet, you can sign up here:
Frequently Asked Questions
How much does it cost to have a Google account?
Google accounts are free
Should each educator create their own Google account?
No, this is not required. As a service, you can create one and share the login between all devices.
What else can I do with a Google account?
You can store important phone numbers especially local emergency contacts and it will sync across all devices. You can also use Google Calendar to share important upcoming events with all devices.
Their privacy statements can be found online here: https://www.google.com/policies/privacy/