No.
Octane is a colorless liquid that will boil around 125ยบ F. Octane Ratings are only a measure of the fuel's tendency to burn in a controlled manner, rather than exploding in an uncontrolled manner. Explosion in an uncontrolled manner in an engine is what is more commonly called knock or "dieseling".
The best way to stop vapor lock in my experience was when I wrapped the fuel line with thermal insulation between where the line goes vertical to the cylinder head to where it passes over the intake to the #1 cylinder. I exercised my redneck tendencies to bind it down with coat hanger wire.
