Captain Picard Facepalm

You could call 911 before 2001

On February 16, 1968, the first-ever 9-1-1 call was placed by Alabama Speaker of the House Rankin Fite, from Haleyville City Hall, to U.S. Rep. Tom Bevill, at the city's police station. However, 911 systems were not in widespread use until the 1980s when the number 911 was adopted as the standard number across most of the country under the North American Numbering Plan.
I don't always believe Wikipedia, however...

Ya, what they said

Sorry, I was told 911 was named after the event that took place on 9/11/2001.

Osama bin Laden chose the September the 11th date as a reference to the anniversary of the end of the Siege of Vienna (look it up).

The emergency number in the USA has always been 911 to my knowledge; the digits are easy to find in an emergency and on an old rotary phone the 1's took less time to dial.

To my knowledge, there's no link between the two at all.

Eh?