I found that if I go past a gap of .034 on the plugs with my 6AL, the spark gets enough resistance to start cross firing within the cap of my 009. You will most likely need to get an early rotor, or solder a solid copper wire in the rotor to bypass the resistor. I would run a spiral wound plug wire, like from MSD, or Taylor, and non-resistor plugs.
Make sure you're using a "215" rotor (last 3 digit of Bosch part number). The later rotor, like for Vanagon, early CIS Rabbit etc., uses a wider contact tip at end of rotor, which can cause cross firing with higher KV ignition, at higher rpm.
I run 009 with NGK D7EA gapped @ 0.060, fired by Crane HI6R CD box and low resistance, high KV coil, Moroso Blue Max wires, no cross firing to 7500. I replaced an MSD 6A with the Crane.
The performance difference between the Crane and old MSD is quite striking. And the proof was in how the plugs looked after a few miles, after changing only the CD box.