Honestly feel like he could be
Dude is portrayed like Oden. In that while Kuma was a subordinate of Dragon’s, he ultimately followed his own will and wasn’t just a mindless follower.
Like Zoro, he is capable of undertaking immense suffering for those that he loves.
And in present day, dude just did the impossible and willed his consciousness back. Oda is surely going to let Kuma take revenge on Saturn next chap, so I feel like CoC could be used to negate Saturn’s powers.