There are no generic "9th century armor" or generic "9th century weapons" to compare their effectiveness against. You'll need to at least qualify a region or something if you want people to have any hope of responding.

elaborate if you want a good answer. People had armor to decrease the chances of getting killed/hurt. " armor" is everywhere these days, from police uniforms to construction workers.

Is your question about how would ancient armor stack up today? Or just how much " damage" it could take?

This is a really complicated question, because each armor type was made for a purpose, there where always pros and cons... Try finding a specific armor and ask about that if you are interested, better chance of getting something.