Sal has mentioned in the past that their maker in China can't produce 9Cr consistently enough to meet Spyderco QC requirement.
Also, many has used 8Cr on wood, and it performed adequately (as per their test). I'd suggest look up RuslanKiyasov on YT, he did some comparison of Tenacious vs other Chinese made 8Cr (Enlan if not mistaken), and the edge retention of Tenacious blowed Enlan out of the door.

To those thinking it's geometry, the way the rope cutting was done, it's not affected by geometry and the Enlan dulled at the apex (no longer biting into the rope). Unfortunately I don't speak the language, so I can't catch if he sharpened them beforehand to same grit / angle.
With that in mind, I think it still shows one thing: Spyderco demand on QC is high and resulting in high performance knives, even in 8Cr.