That paragraph is supposes to highlight the difference between hadith from the prophet vs haditths that are just oral collections from diff ppl. The author is saying here that the hadith does not carry the same weight as other bukhari hadiths because its not attributed to the prophet and is merely an oral claim by hisham(someone who has memory issues) that “someone said that Aisha said she was 9”

You are quoting the ending parts of the article which have nothing to do with the original argument it presents and simply is there to cleanup and establish the new status quo, and these tiny “things” whatever you call them are meaningless in the context of the greater discussion.

The symbolic part is discussed all through the article (for eg age 40 as a symbol for being wise, and for extra info age 70 in islamic world is considered the timeline for eternity(sorry if I cant explain it well, english aint my first language, but for eg u say to smone like “bro why r u so weak, r u already 70yo?”)

You not liking it does not change the fact that ages were used a lot more for symbolism back then than the actual time since the person has been born. There were no objectively correct ways of knowing smones birthdate back then except for word of mouth (if ppl cared to remember, because islam uses the lunar calendar, its much more complicated to track birthdays and date than how we do today)

Why not quote some of the earlier longer parts about timeline inconsistencies and sectarian incentives, those are up for discussion.