The Google Sheets app is compatible with my Android TV - https://play.google.com/store/apps/details?id=com.google.android.apps.docs.editors.slides&hl=en_GB

From memory I believe I can install apps without a password. I believe even changing Google Play to require authentication for purchases will not enforce this for free applications.

So yes - it is possible to access google data via applications.

If this is not desirable then you either need to use a different Google account or use something like AppLock to restrict access to Google Play and any other applications with permissions you aren't happy sharing with other TV users.

The Google Slides app is compatible with my Android TV - https://play.google.com/store/apps/details?id=com.google.android.apps.docs.editors.slides&hl=en_GB

From memory I believe I can install apps without a password. I believe even changing Google Play to require authentication for purchases will not enforce this for free applications.

So yes - it is possible to access google data via applications.

If this is not desirable then you either need to use a different Google account or use something like AppLock to restrict access to Google Play and any other applications with permissions you aren't happy sharing with other TV users.