While WBFS is excellent, the Wii modding scene has evolved. Many modern users prefer:
To play Mario Party 9 on your original hardware, your Wii must be "softmodded" with the Homebrew Channel. Follow these steps to set up your file correctly: Mario Party 9 Wbfs File
from the Homebrew Channel. The loader should automatically detect Mario Party 9. If not, go to Settings → Hard Drive Settings → Set “Game/Install Partition” to USB. While WBFS is excellent, the Wii modding scene has evolved