The same Credential ID cannot be on more than one device, as Credential ID's are specific to each installation of the VIP Access application. This means that each time you install, re-install, or switch devices, you will receive a new Credential ID on the VIP Access application and each device will have its very own Credential ID.
Credential IDs are generated at random and cannot be manually changed. If Credential ID's could be manually changed, then there is a possibility that someone else could use your Credential ID to authenticate as you and steal your information. Check with the site administrator to determine if more than one Credential ID can be registered with your user account.
You can register your Credential ID on multiple sites that use VIP Access.