I think this is how it determines the time - it uses its internal time to the web server, but uses the seconds from your local system time. So as long as your pc is close to "real" time, it looks like its just syncing to your pc.
So.. what you can do is open up your clock, change the seconds to 59 seconds, hit apply. You'll see the Amex site display jump ahead to 59secs, and then turn over the to the next minute. If you repeatedly do this, then you can basically keep advancing the time it displays by a minute, meaning you can get into the game quicker.
Now, I'm not sure if that really plays any importance, like if I trick it into thinking its 9pm when its still 8:45, I'm assuming they somehow stop it. However, if your pc clock is LATER than the real time, you are basically going to always lose, as you don't even get to play until everyone with the correct time has already gotten to go. So it might be good to do this to at least buy yourself a couple minutes so you don't completely miss out.
Didn't do me much good though as I still didn't win the Zen.