How is time written in a novel?

[dancer]

In the AP Stylebook, it says time should use numbers: 1 p.m., 10 o'clock, et.

In novels, I have seen one to nine written out: seven p.m., nine p.m.

When it's something like 9:30 p.m., is this the way it should be expressed in a novel, or should it be written - nine-thirty p.m?

Thank you for your help.

[DanielScocco]

This post might help:

http://www.dailywritingtips.com/10-rules-for-writing-numbers-and-numerals/

I think it might be a matter of style and personal preference.