While Nintendo does not officially release these sounds for public use, enthusiasts often find them on community repositories:
The SoundFont is not perfect:
The console's audio chip read the MIDI files and played the corresponding samples from the internal soundfont. The Origin of the Wii Sports Soundfont wii sports soundfont
Wii Sports’ soundtrack was composed by (famous for the “Totaka’s Song” easter egg) and other Nintendo composers. The game’s sound aesthetic is characterized by: While Nintendo does not officially release these sounds
HCS Forum - Wii Sports "Soundfont"!! - Halley's Comet Software wii sports soundfont