There could be. However, the availability really depends on the popularity of these two characters among fanfic writers. Some pairings are more common than others, but with enough interest, someone may have written a 'kick buttowski x kendall' fanfic. You might also try searching on Tumblr, as sometimes users post links to fanfics there.
Some fanfics could be about Kick Buttowski's dreams and aspirations. He's always full of energy and ideas. So a fanfic could tell a story about him aiming for a big skateboarding competition and all the training and self - discovery he goes through on the way.
Well, it depends on the author's imagination. Some fanfics might show ultra instinct as an overwhelming power, while others might have a more nuanced take.
Moreover, Kick's character has room for growth and development in fanfics. Writers can take his basic traits and expand on them, perhaps showing him learning important life lessons or facing more complex challenges than he does in the original show. This allows for a great deal of creativity when it comes to writing fanfics about him.
There are indeed Naruto fanfictions where he has Ultra Instinct. Fanfiction writers like to experiment with different power combinations. By giving Naruto Ultra Instinct, they can create really exciting battle scenes. For example, Naruto could use Ultra Instinct to dodge attacks more effectively during a fight with a powerful enemy like Madara, adding a whole new dimension to the story.
You could write a fanfiction where Goku teaches others about Ultra Instinct. Maybe he tries to pass on this power to Gohan or Trunks. This would involve Goku having to understand the power more deeply himself in order to teach it, and it would also be a great way to develop the other characters.
Goku definitely masters Ultra Instinct in the manga. This transformation gives him a huge boost in power and allows him to take on even stronger opponents.