Yeah, bullet-punch. He'd decimate in Gen 6 Ubers, though, even without fairy attacks. And considering he runs unnerve and a fire attack often enough already the boost in usage Scizor would get in response wouldn't stop him.
Woah. I'm not a fairy-type hater nor a 1st gen/mewtwo fanboy. I just don't get how mewtwo's new form could be fairy when it looks more like a mutant alien is all. Also i read plenty of fairy folklores long before sylveon was revealed.