While Home is positioned as a way to add Assistant to your domicile, it's only fully usable for a single person. You cannot have more than one account tied to Google Home, so all the user-specific data accessible on Home belongs to whoever sets it up. The only option here is to disable "personal results" so other people can't get into things like your calendar.
It should be able to figure out who's who, though. Google is able to recognize voices—you train your phone's OK Google trigger so only you can set it off. Home should have multiple accounts and ID you by voice, returning personal results for the right account. The Home settings currently has a place for "Linked Account(s)" (note the plural), so hopefully this is coming soon.