We design the keynotes so that the big reveal of the product happens around 40 minutes into the presentation. When the big image of the product appears on screen, we want the time shown to be close to the actual time on the audience's watches. But we know we won't hit 40 minutes exactly.
So just to be safe, Forstall explained, Apple added another extra minute or two to provide a little bit of a cushion in the event of any slight holdups or delays.
https://www.engadget.com/2014/04/14/why-9-41-am-is-the-always-the-time-displayed-on-iphones-and-ipad/