Is 9.7:1 compression on iron heads too much for 91 octane

Nope. My next one will be over 12:1 on pump gas...maybe as high as 12.5:1. and I’ll run full timing...35-36 total.

With iron heads on 91 octane at sea level? And what's your dynamic compression again?

That big static number doesn't mean a thing if you're not going to stick to the question. Iron heads, at sea level, on 91 octane with a small cam. We're trying to answer the OP's question, not blow sunshine up his butt with numbers he can't run because his build is completely different than yours.