Was hired as a temporary employee (not through an agency) for one year and was told by HR that maybe after 6 months they would consider bringing me on FT. Would it be better to express my interest with HR instead of my manager since they were the ones who originally mentioned it?
seconded, you saying anything to HR directly won’t do anything but annoy your manager. (You’re opinion is worthless to them anyway). Your manager is the one you want to talk to, they’ll make a case that you’re needed.