I believe if the Kyuubi was released then Madara could control it. Sasuke didn't control the Kyuubi, he surpressed it and kept Naruto from releasing its power. VERY different. Madara may be able to do that as well. Naruto may confront him, try to go four tails, and Madara may surpress it. Madara still doesn't have the nine tails power he wants.