[Altimas]

No passenger car runs around 9:1 AFR under normal conditions that is functioning properly.
That would obviously result is extremely poor gas mileage and would make the engine make less power and black smoke emit from the tailpipe.
Under part throttle conditions cars with three way cars should go slightly leaner than 14.7:1 and slightly richer so as to have the cat work properly to reduce all the measured (bad) emissions.
Under full throttle they might go as rich as maybe 12:1 for turbo cars but as you said around 13:1 is about the perfect AFR for most cars.

Tuned rotaries, on the other hand, may go as low as ~9:1 AFR for highly boosted applications since even 1 detonation on a rotary can kill the apex seals.