Checking the version of Centrify on the Mac and uninstalling the Agent are at the same location. Go to System Preferences > Centrify. In the Welcome tab, look for " CentrifyDC version" to get the version number.
Just to go over the basics, have you done the following?
1. Log on to the Mac with a local admin account.
2. Go to System Prefernces > Centrify.
3. Click on the Uninstall button.
Please note, if you are a Centrify customer, you have 24/7 access to support if this does not resolve our issue. https://www.centrify.com/support/customer-support-portal/contact/