If I had a plot that was all set in advance, why would I want go through the agony of writing the novel? A novel is a kind of exploration and discovery, for me at any rate.
Once a novel gets going and I know it is viable, I don't then worry about plot or themes. These things will come in almost automatically because the characters are now pulling the story.
Characters are incredibly important, but I tend to build them around the plot during the outline stage. However, once I'm writing the manuscript, the characters I'm writing dictate how the plot unfolds.
I read Claire Messud's 'The Emperor's Children,' I read Joseph O'Neill's 'Netherland' - but to me, they're not 9/11 novels. In 'The Emperor's Children,' 9/11 felt to me like a piece of the plot; the novel wasn't wrestling with what 9/11 meant. And 'Netherland' felt the same way. I liked both books a lot but I don't see them as 9/11 novels.
When we try to push the envelope, there are certain sectors of society that say this is a Zionist plot to sort of destabilize our country, or this is an American agenda.