Good day vanakornnicholson,
This is by design that deactivated user's agenda is displayed in Service Calendar from V8 to V9.
Since the User Type category is populated with information about Disabled users (as shown below), the schedule of disabled users appears in All Resource. Therefore, we preferred to use the User category to filter the enabled and disabled User schedule views in V9 Online environment.

Hope the above would help.
Regards
Johnny