You better go in early October at the latest because they turn off the water at most water station by Oct. 15.
If you're going to do it in one day then the only bailout options I know of would be to stay in a hotel near the North Rim and make it a 2 day hike. You'd have to google the logistics for that and check likelihood that a room would be available.
The only other option would be to carry a lightweight sleeping bag and just crash near the trail where you wouldn't be seen by a ranger. After all you are in the Grand Canyon and there is no way out but UP. No one is going to bail you out in the canyon.
