It is seeming to me that all vets advice a little differently.
With some I've had cats cut off food at 10 p.m. with water always available. Then it was changed to no food and water after 9p.m.
Another said no food or water after 8 p.m. and the new one I am using says no food after 8 p.m. and no water after midnight.
I've always kind of used 9 p.m. as the cut off time for food and water, figuring that by the time I get the cat in for their surgery and it actually happens then it will be 9 a.m. or after and they will have been fasting for a full 12 hours.
So far I've had no trouble with cats vomiting and having problems that I've been told.