Hi,
Currently there is no build-in way to book a meeting with the PowerShell command. We can only use Outlook to achieve this. And if the VIP user is the organizer of the meeting, you should have Send As permissions for VIP's mailbox, so that you can use Outlook to book a meeting for the VIP.
You could use the following command to add the Send As permission:
Add-ADPermission -Identity "VIPname" -User <DelegateIdentity> -AccessRights ExtendedRight -ExtendedRights "Send As"
Notes: The Identity parameter requires to use the Name.
This example grants Send As permissions for Aaron Painter to Terry Adams's mailbox:
Add-ADPermission -Identity "Terry Adams" -User AaronPainter -AccessRights ExtendedRight -ExtendedRights "Send As"
After completing this command, you have the Send As permission, and then open Outlook and organize a meeting room for the VIP user.