Whenever Users login to any of the UC applications (UCCX, Unity, UCM, etc.) it requires the username to be case senseitive. How can I change it so that the username is not case sensitive?
The short answer is that you can't change the behavior. The underlying GNU/Linux platform is case sensitive. I believe some of the products, such as CCX, may have enhancement requests to emulate the Microsoft behavior of case insensitive usernames. I wasn't able to find any of these offhand though. If no one else chimes in with specific caveat IDs or alternative options I suggest filing a feature request with your Cisco AM/SE to make your voice heard.
If you're running CUCM 9.0.1, then you may be encountering CSCub77825, "CUCM enforcing username case sensitivity for ldap authentication".