Hi,
Except Samsung, for UFS there is no ISP pinout available for other devices,
all UFS data lines are directly connected to the SoC.
So you have to pry the surface of the SoC very carefully to find the ISP pinout.
Currently, there are many schematic software available in the market.
You may find it easier to find the pinouts with this type of software.
Like the picture I've shown below, I use Pragmafix, which was developed by my friend,
and also sold officially by Martview, I can easily find the location of the UFS Mi 9 pinout that you asked for.
![Mi-9-UFS-Pinout.png](https://i.postimg.cc/qqL1mk6T/Mi-9-UFS-Pinout.png)