@StatistiX If you pay attention to the past two CDP Releases (7.1.7 august 2021, 7.1.8 august 2022) you can get an idea of timing for 7.1.9. That said 7.1.9 is expected very soon and also expected include support for redhat 8.8. Due to not knowing what if anything is impacted in 7.1.7 or 7.1.8, i would recommend waiting for official release of 7.1.9 for rhel 8.8 upgrade.
If you need official response on using redhat 8.8 with current versions, please open an Upgrade Planning Request ticket with Cloudera. This process will include evaluation of current environment and allow you to have that conversation within your support rep.