Never studied Darwin in school, that I recall, excepting a "Great Books of the Western World" course where we read an abridged version of The Origin. My understanding of Darwin's views on religion are based on having read any number of biographies, other scholarly works regarding Darwin, Darwin's autobiography, his notebooks on "Metaphysics and Morals," and many of his letters.
The important point is where his thinking arrived at the end of his life.
At the end of his life Darwin was a non-Christian agnostic, as he had been for about the last three decades of his life. If you're thinking about the story of Darwin's deathbed reversion to Christianity, it's a myth.