What's the best time to bike on the City Wall of Xian in early Oct?

Yes, there are performances every day in the South Gate area. In 2010, they are at 0930, 1030 and 1630. Not clear about the schedule this year.
I think biking in the day time is better. It is a little dark at night. Or maybe you can go to visit it in the afternoon when you can bike and enjoy the night scene at the same time.