OnePlus 9 Global_OxygenOS_188.8.131.52
Launch MsmDownloadTool V4.0.exe.
Power your device off.
Maintain volume up and volume down keys to get into Qualcomm EDL mode.
Plug your device to your computer using stock OnePlus cable.
Click on Enum to be sure your device is detected and press Start.
Wait ~300 seconds.
Enjoy your brand new device.