He's happy to talk; after all, he's just as curious, too.

9S shakes his head. "I'm a mechanical being modelled after my human creators." He salutes, left hand over where his heart would be. "I'm a YoRHa Number 9 Type S model, but I usually go by 9S."

It's all said with a smile, though if his eyes weren't covered by his visor, it'd be obvious it doesn't quite reach his eyes. He's proud of being an android, but proud of being YoRHa? Maybe once, when he was filled with glorious purpose, full of belief in Command, but not any more.