I have a work on a personal project with Magento 1.9.
I installed the sample database, it is working without any problem in its functionality. But the page layout of a configurable product is strange. The example configurable options: Color and size. And the buy button, are staying down there after the photos of the product.
However, in a configurable product of the sample base. The layout is normal, with the "color" and "size" options in a block just below the product name and price.