I need to display attributes (additional information) of each simple product associated with the configurable product in Magento 1.9.
This extension fites your needs: Better Configurable Products
But be aware that it changes substantially how configurable products work internally, so there are some rewrites of important core classes. Though the overall quality is way above the "Simple Configurable Products" extension.
Also you should not expect it to work out of the box. This is not a "one click install and forget" extension, it should be installed and configured by a developer.