Oh, dude, that's like 17 hours. I know, math is hard, but trust me on this one. So, from 9am to 2am, you've got a solid 17-hour stretch to do... whatever it is you do for 17 hours straight.
12 hours.
5 hrs afrter 9am is 2pm; 5 hrs afrter 9pm is 2am
21
From 9am to 6:30pm is 9 hours and 30 minutes.
Nine hours.
5 Hours
6 hours
9 hours
21 hours
There are zero hours between 9 am and 9 am.
11 hours