Just ran into a customer running CUCM 9.1.2 where I was tasked with adding another subscriber to the cluster. Good fun with a new C240 chassis, and all things went as planned until I found I could not install VMware tools on the server.
Given it's version 9, I first tried the simple method to install from the vSphere client. Normally you can right-click the guest server and choose Guest | Install / Upgrade VMware tools. My experience is this is typically a 30 second process, but after a couple minutes I felt it was failing and cancelled the install from the same menu.
I was able to edit the server properties through the vSphere client and under the Advanced section, checked the Check and upgrade Tools during power cycling option, but I wasn't in the mood to wait for a graceful restart, nor interupt any services.
Instead, I SSH'd to the server and ran "utils os secure permissive". This basically stops the CUCM firewall.
I then tried the install via the vSphere client and boom, 30 seconds or so later they are installed an up to date.
Then, for good measure ran "utils os secure enforce" to re-enable the firewall.
For your install options per app and version, see: http://docwiki.cisco.com/wiki/VMware_Tools
For a similar thread and my inspiration, see: https://supportforums.cisco.com/discussion/12274396/cucm-105-vmware-tools