While the Expanded Universe of Star Wars novels are no longer considered official canon, they have clearly acted as both direct and indirect inspiration for the current crop of films.
While this similarity almost certainly means that the plot synopsis actually came directly from the novel, there’s always the possibility, however remote, that this is because the novel is actually inspiring the film.
The novel in question takes place during the same time period in the Star Wars universe that an Obi-Wan Kenobi movie would be expected to be set, anybody who was working on a script for such a film, and, again, we don’t actually know that anybody is, would almost certainly make themselves familiar with the book.
Han Solo and Leia had a child that turned to the Dark Side in the novels before Kylo Ren was ever a reality, and Grand Admiral Thrawn made the leap from Heir to the Empire directly to the Star Wars Rebels animated series.