The vast majority aren't menstruating, and I doubt the few that are would have anything close to a "voluptuous" body. No matter the few extreme cases where a nine year old is somewhat developed, they will still obviously appear as more of a child - both physically, and even moreso intellectually and emotionally - and thus, any grown man who is sexually attracted to a nine year old is still messed up in the head.
I realize people will bend over backwards and make arguments in defense of religion that they wouldn't think of making in other circumstances, but people have abandoned all reason when they jump through hoops to try to rationalize an adult man having sex with a nine year old girl. Get real people.