Is it polite to send a message at 9 pm?

Whether it is polite to send a message at 9 pm depends on the specific situation and cultural background. In some cultures, it may be very late at 9 pm, so sending information may be considered impolite, because it may disturb the receiver. In other cultures, it may be as early as 9 pm, so sending information will not be considered impolite.

In addition, in some cases, it may be considered inappropriate to send messages at 9 pm, such as when others are resting or sleeping. Therefore, when considering whether to send information, it is best to consider the cultural background and current situation of the receiver. If you are not sure whether it is appropriate, it is best to ask the other person's opinion or preference first.