Eli5: Why were the Boeing Max 9 planes immediately grounded but not the Max 8’s?

Question

I don’t understand why regulators immediately grounded the Max 9’s, but it took two Max 8 crashes before they were grounded.

In: Other

Answer 1

This is like asking why was a 2023 honda recalled, but the 2018 wasn’t?

They may look similar, but they are very different.