There’s never enough time to get your message across. Even Fidel Castro, famous for giving six-hour speeches, had plenty more to add.
If you’re given 8 minutes, take 8 minutes minus 7 seconds, not 9 minutes. The extra minute is selfish. The extra minute doesn’t actually make that much of a difference in how much you are able to communicate.
In fact, it’s the non-verbal communication we remember, and if you are rushing, apologizing and stepping on the toes of the person after you, that’s what the audience will take away.