The Schooldays of Jesus is not, as it happens, about the schooldays of Jesus. It is the Man Booker-nominated sequel to The Childhood of Jesus (which, you guessed it, did not once refer to the childhood of Jesus either). J.M. Coetzee is now so much part of the literary pantheon, so liable to be rewarded by the critical classes and the academic industry surrounding him, that he no longer needs to worry about basics such as having a title that makes sense.
He should still worry, one feels, about telling a story worth following.