Hi pushit94,

Your personal GMAT Exam does not begin until one of the Testing Center Moderators physically escorts you to your workstation and logs you in. You might actually begin your Exam a little before (or after) 9:30am, depending on how busy the Center is.

As a general rule, it's best to arrive early - remember that it takes time to go through the 'check in' process and the Orientation Program (when you're sitting at your workstation). If you are sufficiently late for your appointment, then the Testing Center staff can void your appointment (while keeping your money).

GMAT assassins aren't born, they're made,
Rich