I don't have the game but I would like to speedrun it without it counting as emulator. Would using a regular dvd+r with wii party burned on it be considered as an emulator run ?

If you run Wii Party without an official disc copy in a Wii/vWii, then it is unofficial and must be marked as an emulator

To add more context to what Amun said, speedrunning with this method would need to be marked as emulator as burning Wii Party into a DVD is not an official way of playing the game. Although it may not load that much faster, it is important to keep the emulator rule consistent.