In your case you can't call a cell when 911 is dialed.
I happen to know you vendor is working on that and it may be possible in near future.
1 - check COR 10 in the Class of Restriction form. If it's not blank go to 100 - be sure it's blank.
2- check your digit mod. If 10 has 'absorb 1' then pick one that doesn't have it. In the digit insert field be sure this is there: '<T01>'.
3 - In your route assignment, probably 10, you should see trunk group 1, COR 10 (or your new one) and Digit mod 10 (or your new one) - Very important: Your route type must be set to 'emergency'.
4 - In the form ARS Digits dialed, you should have 911 go to route 10. - Note not 9911
5 -Now for notification. The phones you want to notify need to have emergency notification enabled in their COS. Then create an emergency notification Hunt group and put them in it.
6 - Test.
7 - Now go to system speed dial and add 9911 with the actual of 911.
8 - In system speed dial again add '911*' with an actual of <your extension number> - this will stop accidental 911 calls.
I'm finding it hard to understand why 911 isn't working. I know who set it up so it surprises that mistake would have been made.
Ralph