Mohammed the prophet in the religion of Islam married a 9 year old?

If you lived in a culture and a time when the best, if not only way to protect a widow or other female was to marry them and you did so just for that purpose, would that make you a pedophile? (Widows had only the option of remarrying or prostitution, What might be the story behind the young girls? What might He have saved them from?) Why was it that while he had more than one wife, that until His first, Khadija, died none of His others ever became pregnant? If you have an agenda to prove something, then it becomes quite easy to see actual facts in a certain very biased way, to see facts where there are none, and to manufacture them if needed. And if you are wondering, no I an not a Muslim. I am a Baha'i, and to the greatest part of Islam I am considered much more a pariah and infidel than any Christian or Jew, so if I had any agenda, it would be unlikely to be one in Muhammad's defense.