While The Kite Runner is certainly a novel (fiction), it would be accurate to describe it as semi-autobiographical because Hosseini grew up in the same Afghanistan that Amir experiences, fled the country when the coupe and Soviet invasion took place, settled in the Fremont, California area just like Baba and Amir, and watched his father struggle with the complexities of being an immigrant who cannot return to the homeland.
As the previous answer states, the novel is historical because of the past and current events it is centered upon, and it is the first fictional novel written in English about Afghanistan and Afghan immigrants. In that sense, it is a groundbreaking work.
I would certainly label Khaled Hosseini's book, The Kite Runner, as a fiction novel. More specifically, it should be categorized as historical fiction, since many of the events were based on the real-life experiences of the author as well as the nation of Afghanistan. The Kite Runner has been called the first novel ever written in the English language by a native Afghani writer. Although it is now a staple in high schools around the country, I would not label it as a teen novel since its storyline encompasses far more than just the life of a teenager. It is a fine novel that all Americans should read in order to learn more about the all-important nation of Afghanistan. I have heard several people claim to understand better the plight of today's Middle East after reading The Kite Runner.
In other words, it can be called docufiction. Or as Sparknotes puts it: Bildungsroman; Redemption story.