What was the wisdom for Rasulullah's marriage to Hadhrat Aishah (radhiyallahu anhu) at the age of 7 or 8 or 9 years?

Answer

The wisdom is known to only Allah Ta'ala Who had commanded the marriage. One likely wisdom, is to separate the munaafiqeen (hypocrites) from the Mu'mineen. Hypocrites will fall into the trap of the kuffaar who are assailing the noble character of Rasulullah (sallallahu alayhi wasallam). If a doubt enters the heart in consequence of kuffaar propaganda then understand that it is a portion of nifaaq. Many modernist 'muslims' who are in reality munaafiqeen at heart, openly display their hidden kufr when they justify kuffaar propaganda with baseless interpretations in the attempt to assuage the kufr palates of their kuffaar masters