While the list is incomplete, the only bug-fixes officially reported are for a Valgrind memory error and a glInvalidateFramebuffer issue. Also worth noting is that the RadeonSI Gallium3D driver with Radeon HD 8000 "Sea Islands" hardware is now using the HD 7000 "Southern Islands" code-path in the LLVM back-end for LLVM 3.3. LLVM 3.3 doesn't have support for recognizing Sea Islands, but the AMD GPU LLVM back-end code between Sea Islands and Southern Islands is the same.
More details on Mesa 9.2.2 are available from the release announcement and documentation. Meanwhile, Mesa 10.0 is shaping up to be a very exciting release and will be out in hopefully just over one month.