No - 911 is for serious EMERGENCIES. If you aren't sure about animal control, call your local animal shelter and ask if they've got it (or any advice for your situation), or call the basic, non-emergency number for your local police department and ask them.
EDIT - Every police department or sheriff's department/highway patrol has their own number for their department headquarters. Same goes for the fire department. You call 911 if you have a very urgent emergency at hand. If you aren't sure what your local department number is, just Google it like you did!
I'm glad they were able to direct you and really hope the situation is resolved. If she is going to take care of that cat and considers it "hers", she needs to give it proper vet care in addition to food/water. If it is sickly/dirty, it needs to be seen by a vet. It's rather cruel to deny it medical attention if something is wrong. Good luck! I hope for a peaceful resolve :)