After fresh install of Splunk 9.0.1, splunk cli commands (example 'add oneshot') report the following warning message:
WARNING: Server Certificate Hostname Validation is disabled. Please see server.conf/[sslConfig]/cliVerifyServerName for details.
This warning was not seen on prior releases of Splunk (8.2.x).
Also, this warning message did show up on 'splunk start' after the fresh install. Looks like this warning message is bug in 9.0.x for a fresh install/start of Splunk