Most all instructions for the G7 will work for the G9 family. You can probably step through the instructions and do it yourself. If you have questions, we can work together on Sunday or after.
First get the bootloader unlocked. That will be easy but you have to read the Motorola website and sign up as a developer. The G7 instructions should get you the rest.
He is correct that there are no ROMs to install yet. First, TWRP is released, then Lineage, then maybe /e/. We can only work up to TWRP at this point. Good news, after TWRP is installed, you can install Magisk to have root or other functionality.