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

My stock compression 340 motor(TRUE compression of 9.4) would start to detonate right at the finish line, in the heat of the summer at 4400 foot elevation With a mopar .474 280 duration cam.
If i knew then what i know now, it would not have detonated.

Mine was detonating because of eng coolant temp and eng bay air temp.
Smoothing up the combustion chamber would have helped out a lot as well.
Sealing off the heat crossover in the intake.
opening up the headers instead of running them thru the 2 inch full lenght exhaust, i had at the time.
Header Wrap headers.

Just a little food for thought.