I have no intentions of doing this at all
But would it be allowed if someone thoroughly studied a novel not assigned to them by their school and wrote about it in the exam?
If you mean, could someone study another text
on the official VCAA list and do that on the exam for Section A, then yes, as abc said. You get to nominate your own text and prompt as per
this so there's be no contradictions on your actual booklet. I believe the school probably ships them to VCAA informing them that all the essays will be on the two texts they've studied, so there might be some administrative problems when they have to send it to a different teacher. If I remember right, teachers can only mark essays on books they've taught in that year, or one year previously, so whilst there's no way of knowing who exactly will end up with your essay, they are careful to distribute them to particular people. But if the wrong essay ends up with the wrong assessor, they just return to sender and it gets sent out again to someone else.
However, if you're asking whether you could just write on any old novel and still get marks for the quality of your ideas and your writing, the answer is a resounding no. I've heard of people doing this in the past and none of them scored above a 2/10
