Nine grinned as she commented about what he had first said to her. She did pay attention. That was fantastic. The observant always lasted longer than the nonobservant.
...usually. Still, he was pleased she had caught it. And given she didn't seem like the time to be dangerous or try to kill him, he might as well show her his beloved sonic screwdriver. He reached into his worn but favorite black leather jacket and pulled out the screwdriver. Anyone passing by might think it one of those toy screwdrivers Doctor Who fans could buy online.
"Sonic screwdriver. Though some call it a probe. But it's a screwdriver," he said, insisting upon its name. "Depending on the settings, it can scan biologicals for information. I first suspected you though because you have that experience in your eye that you're use to weird. So I took a shot in the dark of it being aliens. Could have been ghosts for all I knew though. But it was aliens and that's fantastic!" he said happily.