The Kite Runner, is portrayed as a work of fiction, yet one can argue it is largley autobiographical. Would this work as a thesis?First time back...

Is your assignment a literary analysis, an argument, a
review?  Depending on your assignment, your thesis statement might need some tweaking. 
If you are simply writing an analysis, the thesis is on track.  You might consider
claiming something like: Khaled Hosseini's The Kite Runner earned
its position on fiction bestseller lists, but its autobiographical elements and
portrayal of Afghanistan offer readers a gritty
reality.

When doing your research, look for interviews with
Khaled Hosseini so that you can use the author's own words as proof that aspects of the
novel are autobiographical.  Just be careful because Hosseini has made it clear in
interviews that the situation with Hassan and Assef are completely fictional.  When
discussing the real elements, consider Amir's relationship with Baba and Hosseini's with
his own father (or what Hosseini doesn't say about his relationship with his
father).

Keep in mind that the key to an effective thesis
is that is must be provable, must be a statement, and it needs to give you enough to
work with in your paper.  That's why if you add the aspect of "a realistic portrayal of
Afghanistan" to your thesis, you will have more to work with in your body
paragraphs.

The links below are a good place to start. Good
luck!