Why doesn't my Play History list different users

I only share my Plex server with my son who has his own Username and doesn’t know my ID password yet when I look at my Play History his viewings are listed under my username. I know they are his viewings by the device listed (Xbox One) which I don’t use.

Sorry the title of your post and the question you ask seem to be at odds with each other.
Are you looking in the dashboard?

Does your son live in the same household with you, which means his devices are in the same local network?
If so, he might be using the DLNA client on his XBox, instead of the Plex app.
And since DLNA doesn’t support user authentication, it means that every access per DLNA is attributed to the server owner’s account.

Another idea: Do you have anything in
Settings - Server - Network - ‘Show Advanced’ - “List of IP addresses and networks that are allowed without auth” ?

No, my son lives in a different city than where my server is located. There are no IP dresses listed as allowed without authorization.

Yes. In my Dashboard when I check Play History it only lists one user even. though both my son and I are different users.

Looks like he is a member of your Plex Home.
Is it possible, that he ‘Switched User’ once and since then is using your account instead of his?

Do also verify that it is not you, who ‘switched user’ by accident.