From Kuma, we’ve seen how the Buccaneers revere Nika and see them as a superhero. Vegapunk theorized that devil fruits come from the dreams of people. I think the Buccaneers’ crime was creating the Nika fruit.

This is a stretch but I believe the Buccaneers were an oppressed race even before their crime mentioned by Saturn. They may have witnessed rubber nullfying lightning (considered the power of god) and imagined a superhero made of rubber. The hero would be the most free person because they would have the power to defy god.”

I think the Buccaneers’ crime is creating all devil fruits. I believe this is unique to their race due to no others, such as Fishmen and Wano citizens, being able to manifest fruits despite the atrocities they’ve faced. In order to create fruits, people have to be able to pass their will into inanimate objects. This could be the unique trait of the Buccaneers that Vegapunk mentioned. And this can explain why Kuma hasn’t shut down completely.

In Chapter 1058, Kuma was still active and responded to Dragon. That same day Lulusia was destroyed and Saturn more than likely flipped the switch thinking that the leadership of the Revolutionaries were taken out during the two events. But, flipping the switch allowed Kuma’s will to possess his mechanized body and fulfill his desire to protect Bonney. Somehow he was able to sense her location and possible danger status as she was trapped in the eddy at that time. Once Kuma got to Egghead and saved Bonney from the initial blows, he “shutdown” because the Straw Hats could move again and Bonney was no longer in imminent danger. So Atlas had to carry him away. But as soon as Bonney was in danger again, Kuma reactivates to guard her from the oncoming beams from the pacifista.

When Saturn asks Vegapunk what’s going on, he cheekly says it’s the power of love. Kuma’s love for Bonney is what made his will to protect her so strong. The unique ability of the Buccaneer’s to place their wills inanimate objects is how he’s able to control his body to continue protecting her.

Through some mechanism, a dying Buccaneer’s strong desire to be the thing or have the power they dreamed of would be transferred into fruit.