The -9 in CR8XEH-9 denotes gap in tenths of a millimeter, so it should be about 0.036". This is fine for the 919, which seems to have enough zap to light the fires even with gaps exceeding 0.040". The wider the gap, the hotter the spark only up to a point -- even if the energy from the coils is sufficient at idle, it may not be at higher loads, where the higher pressures make the formation of the ionization path (necessary for spark formation) much more difficult. Stick close to the recommended gap.
I just bought four NGK Irridium plugs to put in this weekend. The invoice has a statement printed on it that says, "Do not gap these plugs, you might break the electrode!" I have not opened them to check the gap but if they are not right on, I'm just going to gap them for the recommended .035" (recommendation from NGK for the 919).