It was going to be named ''901'' but then Peugeot stepped in with their licence to numbered car names with an ''0'' in the middle, so Porsche must have changed the name to 911.
As an option... I have the brochure here next to me and the first 911 has the 901 as their internal project number. But in 1963 one car with the 901 shown at the Frankfurt Motor Show, but like I said it's also the internal project number.