You realize the event wasn't live, right? And Tim's watch clearly shows 10:09 the second he shows up in the video which was 10:01 at the latest "real time".
I know it isn't live, and it shows because they've been sloppy throughout. Check out his watch at the 20 minute mark, it's way off.
In general, Apple's presenter's watches (and demo devices) show the local time for live events, and they tried to do that here but obviously didn't do a very good job.
But they didn't do that, as I just mentioned and gave a fairly exact timestamp (to within a few seconds) for for you to check that they did not in fact do this.