There is insurmountable evidence that suggests that Aisha was NOT 9 when she married Prophet Muhammed (pbuh).
Consider the following facts:
First point:
Nobody under the age of fifteen was allowed to participate in raiding parities.
http://www.usc.edu/dept/MSA/fundamen...ml#005.059.423
http://www.usc.edu/dept/MSA/fundamen....html#019.4466
However, according to authentic Bukhari and Muslim sources, Aisha participated in the Battle of Badr in 624 CE as well as the Battle of Uhud in 625 CE.
http://www.usc.edu/dept/MSA/fundamen....html#019.4472
http://www.usc.edu/dept/MSA/fundamen...ml#004.052.131
Therefore, Aisha must be
at least 15 years old in 624 CE and thus 13 years old following the Hijra in 622 CE.
Second point:
The earliest surviving biography of Prophet Muhammad (pbuh) is Sirah Rashul Allah by Ibn Ishaq. According to this source, Aisha converted to Islam around 610 CE. In order to convert to Islam, she must be at least 3 years of age to be walking and talking. Thus, she must be fifteen years at 622 CE.
Third point:
Tabari reports that Abu Bakr wished to spare Aisha the discomforts of a journey to Ethiopia soon after 615 CE, and tried to bring forward her marriage to Mut`im ibn `Uday's son. Mut`am refused because Abu Bakr had converted to Islam, but if Aisha was already of marriageable age in 615 CE, she must have been older than nine in 622 CE.
Fourth Point:
Tabari also reports that Abu Bakr's four children were all born during the Jahiliyyah, the pre Islamic period, which is said to have ended in 610 CE, making Aisha at least twelve in 622 CE when Aisha started living with Muhammad.
Fifth Point:
Aisha is reported to have said that at the time Surah Al-Qamar, the 54th chapter of the Qur'an , was revealed, "I was a young girl".
http://www.usc.edu/dept/MSA/fundamen...ml#006.060.399
The 54th Surah of the Qur'an was revealed nine years before Hijrah. According to this tradition, Aisha had not only been born before the revelation of the referred Surah, but was actually a young girl, not even only an infant at that time. So if this age is assumed to be 7 to 14 years then her age at the time of marriage would be 16 to 23.
Sixth Point
According to almost all the historians, Asma bint Abu Bakr, the elder sister of Aisha, was ten years older than Aisha. Asma is reported to die in the 73 AH, when she was 100 years old. Now, obviously if Asma was 100 years old in the 73 AH, she should have been 27 or 28 years old at the time of Migration to Medina (1 AH). If Asma was 27 or 28 years old at that time, Aisha should have been 17 or 18 years old at the same time. Thus, Aisha - if she got married in 1 AH or 2 AH - was between 18 to 20 years old at the time of her marriage.
Refuting Bukhari's hadith:
According to Sahih Bukhari, Aisha was engaged at the age of 6 and was married and consummated at the age of 9:
http://www.usc.edu/dept/MSA/fundamen...ml#005.058.234
http://www.usc.edu/dept/MSA/fundamen...ml#005.058.236
http://www.usc.edu/dept/MSA/fundamen...ml#007.062.064
http://www.usc.edu/dept/MSA/fundamen...ml#007.062.088
Similar accounts are in Sahih Muslim:
http://www.usc.edu/dept/MSA/fundamen....html#008.3309
http://www.usc.edu/dept/MSA/fundamen....html#008.3310
http://www.usc.edu/dept/MSA/fundamen....html#008.3311
Here are some problems with the reports:
Seventh Point:
Reports regarding Aisha's age were recorded during the Abbasid caliphate when Aisha's youth might be deliberately emphasized by scholars to reject Shi'a claims for the descendants of Ali ibn Abi Talib.
Eighth Point:
Most of the narratives regarding Aisha's age are reported only by Hisham ibn Urwa reporting on the authority of his father. All the narratives of this event have been reported through narrators from Iraq, where Hisham ibn Urwa is reported to have shifted after living in Madinah for seventy-one years. It is reported in one of the most well known books on the life and reliability of the narrators of the traditions ascribed to Muhammad that Yaqub ibn Shaibah said, "narratives reported by Hisham are reliable except those that are reported through the people of Iraq". It further states that Malik ibn Anas objected on those narratives of Hisham, which were reported through people of Iraq. Another book on the narrators of the traditions of Muhammad reports that when he was old, Hisham's memory suffered quite badly.
Ninth Point:
Muhammad is attributed to say, "A woman must be consulted and get her permission to make the marriage valid". According to another report, Aisha at the age of nine was rather more interested to play with toy-horses than to take up the responsible task of a wife. Hence, The permission of an immature girl cannot be a valid authorization for marriage.
Tenth Point:
Comparison of hadith of Aisha's age with hadith of Laylat al-Qadr, in which 1 was used for 21, 3 for 23, 5 for 25 and so on, suggest that maybe Aisha's reports were transmitted literally and 16 became 6 and 19 became 9, as it is a way of talking in Arabic language when base is already known.
Eleventh Point:
Hadiths regarding Aisha's age of marriage in Sahih Bukhari was rejected 100 years before it was added to Bukhari's collection of hadiths by IMAM MALIK.
NOTE: This thread is not meant to appease critics of Islam. After all, Mary gave the virgin birth at the age of 11. My goal is to reach the truth. I have provided 11 points, I challenge any Muslim here to refute them.