1- We dispute that she was 9. Our sources indicate she was most likely 17. This is not child marriage. So tell non-Muslims that the hadiths which claim she was 6 or 9 were fabrications and exaggerations by Aisha to show she was very special and sought after. So just be firm and tell them it’s not true.
2- As for Lady Fatima (a) and Imam Ali (a), you can see this video at minute 27 and onwards:
3- She was 11, 12, 13, and 14 or 15
4- Yes the Imams and Lady Fatima are superior to other prophets. Not the same for Lady Zaynab, Um Kulthum and others. They had the minor infallibility according to many scholars.