I want to upgrade RHEL 8 to 9, but RHEL 9 repositories are not listed in RHEL 8

Issue

• I've a created a Content View with the required RHEL 8 and RHEL 9 repositories, but I can't see the RHEL 9 repositories in the host:

  [root@satellite ~]# hammer content-view info --id 3 | grep Name | grep "Red Hat"
  Name:  Red Hat Enterprise Linux 8 for x86_64 - BaseOS RPMs x86_64 8.1
  Name:  Red Hat Enterprise Linux 8 for x86_64 - AppStream RPMs x86_64 8.1
  Name:  Red Hat Enterprise Linux 9 for x86_64 - BaseOS RPMs x86_64 9.1
  Name:  Red Hat Enterprise Linux 9 for x86_64 - AppStream RPMs x86_64 9.1
  

  [root@server ~]# subscription-manager repos --list | grep Name
  Repo Name: Red Hat Enterprise Linux 8 for x86_64 - BaseOS (RPMs)
  Repo Name: Red Hat Enterprise Linux 8 for x86_64 - AppStream (RPMs)
  [root@server ~]# yum repolist
  rhel-8-for-x86_64-appstream-rpms              Red Hat Enterprise Linux 8 for x86_64 - AppStream (RPMs)    0
  rhel-8-for-x86_64-baseos-rpms                 Red Hat Enterprise Linux 8 for x86_64 - BaseOS (RPMs)       0