Family Plan can be accessed on other iOS devices as long as you use your login email that’s registered in the app already. You can check which email this is in the app under Menu > Settings > My Account.
Just note if for any reason, the subscription is disconnected you’ll need to Restore Purchases in the app menu on the device that purchased the Family Plan and then force close and reopen the app on the other devices.
At the moment, Simply Piano only supports Family Plan for iOS devices. In the meantime, if you have upgraded to a Family Plan on your iOS device(s), only your primary profile will be accessible on your Android device(s). All progress for your other profiles on your iOS device will be saved moving forwards after you create them for your family. We do hope to launch this for Android devices soon, but we don’t have a timeline for that just yet.
Need further help? Please email us by going to "Send Us Feedback" in the settings menu of the app or writing to firstname.lastname@example.org.