I think that texting a student should be a fireable offense. It crosses an obvious professional boundary, and teachers should not need that explained to them. There’s no good reason for you to have a student’s personal phone number. If you need to communicate with them, use the school’s official channels. As a parent, if I discovered a teacher was texting my son or daughter, I would consider it a serious red flag, especially with news of another teacher or principal acting inappropriately with a child breaking every other day. My first concern would be what else was going on.