Let’s start with the proof that Muhammad consummated marriage with Aisha at 9 as you claimed then work from there. We have the documented proof that marriage was legal even for 9 year olds in many countries of the world. People in the 7th century lived until what like mid 30s on average?
This isn’t an allegation imposed from the outside. It’s the standard, internal narrative. In some societies, including parts of early modern Europe, child marriage was legally permitted. That does not mean it was typical, expected, or morally uncontroversial even then. Demographic records show the average age of first marriage was still in the late teens to mid-twenties, not nine. And the “people only lived to their mid-30s” argument is a statistical illusion. Average life expectancy was dragged down by infant mortality. Adults who survived childhood routinely lived into their 60s and beyond. Slavery was legal. Child labor was legal. Marital rape was legal. All were once defended as “normal for their time.” We abandoned those defenses because morality is not dictated by what was once allowed.