The top gear on the P9 is 85", on the p24 it's 107". That means (presuming your legs are up to it) that it will move 25% faster. I guess the lighter weight and simplicity of the p9 might make it nippier in traffic. But if you are strong enough to keep up a cadence of 90rpm in top gear, on the P9 you'll max out at around 23 mph, but on the P24 it would be just under 29mph - working much harder, of course.
I don't see how they justify calling the P9 speedy. Just trying to come up with USP, I guess.