If dialling 9 for co access you cant have 911 go out without dialling 9911

If you change line access to 0 you could set it to diall 911 and get the system to add the 0

You can get the system to accept 11 and it add the 99 in front as long as 11 is not a lead number
I would imagine that would not work as people who are used to dialling 9 for a line will do thst quicker than remembering 11 for emergency

“I have not failed. I've just found 10,000 ways that won't work.”