i really don't think marquez is a 9. his chin allows him to finish fights, along with his toughness, skills, and conditioning, but he gets shaken pretty regularly.
he's been down and hurt too many times for me to rank his chin so high. his powers of recovery are as good as you will ever see, but i don't believe that to be completely a product of his chin.
oliver mccall, for instance would take bombs on his chin from HW punchers and hardly react. marquez gets hurt, and relies of stuff other than his chin to survive.