KC's 6X9 Lights are listed at 100 Watts and 191,000 Candlepower. Explorer ProComp's 6x9 lights are also listed as 100 Watts but don't give a Candlepower rating. If you're looking for the most possible light, I'd go with the round light instead of a 6x9. The light amplification from a round beam projector is more efficient.
FYI, KC's strongest light is the Sealed Beam Daylighters, which have 385,000 candlepower (using a 150 Watt Sealed beam element). ProComp's strongest light has a Quartz Halogen 130 Watt bulb. For Comparison, KC's 130 Watt Quartz Halogen light is rated at 300,000 candlepower.