I don't think so... "He is the one who translated the book" would be closer. "çevirEN" means "THE ONE WHO translated." Translator is translated as çevirmen. "O bir çevirmen" -> He is a translator.
However, I think the most accurate way to express "He is the one who translated the book" would "kıtabı çeviren O'dur."
"O kitabı çeviren siz misiniz?" Translation: Are you the one who translated that book?
This is a very strange English sentence - 'one' is rarely used nowadays. I can't see why it couldn't be translated as "Did you translate that book" - but that is marked as incorrect.
You are also correct Julia. - I have given your English question a Turkish answer.
"O kitabı çeviren sen misin?" - Are you the one who translated that book? (singular)
"Did you translate that book?" - Şu kitabı çevirdin misin?
"Did you translate that book?" - O kitabı çevirdin misin?