Is there a function in CUCM 9.1 that will announced Dialed number back to user to verify if that is the number they want to call. I am thinking for "911" called number. If by mistake a user dials "911" they would know to hang up before the call goes through.
You can always simply route to CUC, and use caller input so they verify it they actually wanted to call 911 or not.
Yes, it's called External Call Control Profiles and this feature has ben available since CUCM 8.0.
It leverages the Annunciator service to play an announcment to the caller. Be warned, it's no simple admin task and requires access to developer.cisco.com to implement. Perhaps Cisco will bring this simple functionality into a simple check box one day, but for now, it's a little more complicated.