I still have an alarm clock beside my bed, but one of the nicest things about retirement is that I only set the alarm three or four nights a year. I am no longer forced to make that early morning decision about whether I have to have another nine minutes of sleep.
There has been a lot of speculation about why the snooze feature is set for nine minutes, and some of the theories are pretty bizarre. The one that seems most likely goes back to the 50s and the very first clocks to offer a snooze button. These electromechanical clocks used the existing gears standard in analog clocks to achieve something near a ten minute delay, and designers decided nine minutes and a couple seconds was close enough.
When digital clocks came along, engineers assumed that nine minutes was the standard for a reason, and the nine minute delay has continued - even into today's I-Phones.