If Confucius were 9 chi tall, he'd be between 6-foot-6 and 6-foot-10, which is still quite out of the ordinary, especially in ancient China, but nowhere near as fantastic as your classmate's claim.
(Confucius; were; 9 chi tall) (he; 'd be; between 6-foot-6 and 6-foot-10)
Confucius he
were 'd be
9 chi tall
between 6-foot-6 and 6-foot-10