if you desire 9 degrees advance and have the gas and all that, do like 2 wot passes and see if the plugs are still in the head adn pull them out if they look normal, no gray flaky stuff you might be ok.
i know it depends on your domes the specs not just the squish to run lot of compression and timing, you get the velocitys and bands too high, and pressures off the chart it will blow up.
you might try like 5 degs then up it to like 7 and see if it really makes a difference.