Front Channel SLO (logout endpoint) configuration options do not appear on a 12.9 OIDC client.
This feature exists in a legacy OIDC Client section in 12.8.xx release.
Policy Server Version: 12.9
O/S: ANY
Front Channel SLO is not Supported with in "OAuth/OpenID Connect" in 12.9. Please check the below documentation link.
Configure SiteMinder as OpenID Connect Provider
- Other option is to use the "OpenID connect legacy" to create the Clients.
Note: This feature will be part of next release 12.9.1