CP9 was an organization of spies that the World Government used to achieve its ends in the One Piece universe. Led by Spandam, its agents were responsible for the havoc at Water Seven and the multiple assassination attempts on Iceberg.
Fortunately, there have been canon listings for the power levels of each member in its employ. With a standard marine having a strength approximation of ten, we can use the numbers that Fukurou provided to rank CP9's best operatives (with the understanding that their skills were measured before Kaku and Kalifa ate their devil fruits).
8 Spandam Has A Power Level Of 9
Spandam was the leader of CP9 and a man whose incompetence was unbecoming of his station. With a power level of 9, he is even weaker than a standard soldier in the marines' employ.
To circumvent his galling physical disparities, he uses a number of tools by which to counter his opponents. His arsenal includes shackles that negate devil fruit powers and a sword that is capable of unleashing the full destructive force of an elephant. Despite these assets, he was defeated easily by Robin and Franky.
7 Kalifa Has A Power Level Of 630
Despite being at the bottom of CP9, Kalifa still qualifies to be superhuman since her power level is over 500. The woman was responsible for defeating Sanji and nearly overcame Nami before Chopper provided an essential (and unwitting) distraction.
Her devil fruit power weakened her target and made everything they held slippery. However, since she could only activate it through physical touch, its applicability in battle was questionably relevant. Further, the sheen Kalifa can apply to her adversaries may be undone merely by drying off.
6 Fukorou Had A Power Level Of 800
Fukurou was the CP9 agent to categorize his comrades and a particularly unintelligent warrior. He didn't have as many useful special abilities as his comrades, instead relying heavily on the Six Paths in order to find success in battle. However, he is notably stronger than Kalifa, exceeding her power level by almost two hundred points.
Despite his many advantages over Franky (particularly his ability to fly and his attempts to keep the cyborg in the water), he was defeated by being driven headfirst into the ground. His body left a small crater and provided the first meaningful victory the shipwright had in service to the Straw Hat crew.
5 Kumadori Had A Power Level Of 810
At a power level of 810, Kumadori may not have seemed particularly threatening. However, his mastery over every part of his body allowed him to manipulate his hair and make it obey his will.
As a result, he became a brilliant medium-ranged fighter who managed to contend with Chopper from a safe distance. Even dozens of blows from the doctor's arm point form weren't enough to take him down, requiring a monstrous transformation in order to defeat the operative.
4 Blueno Had A Power Level Of 820
Blueno was a respectable warrior and one of the most daunting members of CP9. At a power level of 820, he easily defeated Sanji on the Sea Train, primarily through the usage of his "Iron Body" technique.
In addition to increasing his mobility, Blueno's "Door Door" fruit could disorient his targets by rearranging their faces. He was such a difficult adversary that Luffy was forced to use his Second Gear for the first time despite the tremendous strain that it placed on his body.
3 Jabra Had A Power Level Of 2,180
With a power level of 2,180, Jabra is over twice as strong as Blueno and a tremendously powerful villain who well surpasses superhuman parameters. His devil fruit allowed him to assume the properties of a wolf and greatly augmented his physical attributes.
Despite his gifts, he prefers to lure victims into a false sense of security before striking them down. This tactic was employed successfully against Usopp, though he would suffer for his insolence during his fight against Sanji.
2 Kaku Has A Power Level of 2,200
With a power level of 2,200, Kaku was the second deadliest member of CP9. His strength is even more impressive when considering that Fukurou measured it before he gained his devil fruit.
In his giraffe state, a single swing of his neck was strong enough to cleave through the Tower of Justice easily. This alarmed Usopp and even Zoro, especially considering he could concentrate his force into deadly "Nose Pistol" attacks. If not for his infighting with Jabra, it's possible that he could have overwhelmed Zoro before Sanji came to his senses and joined the fight.
1 Lucci Has A Terrifying Power Level Of 4,000
With an unprecedented power level of 4,000, Rob Lucci was decisively the strongest member of CP9. He mastered the Six Paths with much greater skill than any of his comrades and served as the leader during the Water Seven operation.
Even though he was defeated by Luffy after activating the Third Gear, he was so formidable that the Straw Hat captain could not move a single muscle after the battle. He had such unimaginable power that he could kill hundreds of adult men as a child.