What should I say when I send a text message to a girl at eight or nine in the evening?

Have you rested? Have you finished your work or study? Then ask some questions that she is good at, which vary from person to person, even if she understands, she can pretend not to understand. Tell her something embarrassing that happened recently to make her smile, or something new, such as a date, a place, and gossip doesn't matter. Stop at that time and don't disturb other people's lives. Continue the next day.