This sounds silly. I don't understand why such a method would work. Also dvd9 support doesn't come with a wii it was implemented with a wiikey/cyclowiz firmware update. So non modded wii's don't read DVD9 i don't believe. I'm really not sure about this.
Wii supports natively DVD9, otherwise, DVD9 support by drivechips couldn't ever be possible. So the drive can read DVD9, and Nintendo can do it anytime with an update.
Nice yeah that's what I was thinking.
I don't think a wii game will ever be on DVD9 though the system doesn't have the power to handle that much data anyway. Everyone said the same thing about SMG that it would be on DVD9. Guess what? It wasn't... 360 games are DVD9. And anyone who has played a 360 game knows that wii games are nowhere near it when it comes to detail and depth of data and graphics. Wii games resemble much closer to the PS2's and XBOX 2gb isos.
I would bet money this is a DVD5.