A trader can place an AMO as well as a Pre-Market order within the time frame of 9am to 9.15am.
In this specific time frame of 15 minutes,
AMO orders can be placed between 9am and 9.14am.
Pre-Market orders can be placed between 9am and 9.08am - here orders are collected, modified and/or cancelled.
Between 9.09am and 9.15am, orders are matched and trades are confirmed. No new orders can be placed in this time.
“I had a hard time convincing my mother that I was not gambling, but making money by figuring.” - Jesse Livermore