PIXHAWK PX4 Pro & FrSKY L9R

Hi everyone, I hope that you are all coping with this lockdown that we have around the world and you are all keeping safe, I have taken the time that we have on our hands to do my drone. I have a Pixhawk PX4 Pro, its a FC that I am not that familiar with so I was wondering if someone out there that can help, I also have an FrSKY L9R receiver and I firstly wanted to know if there is any other way of connecting this receiver to the FC without the need for the PPM Encoder?

Also, do I have to have a specific Power Distribution Board, (PDB), for the FC, the only reason why I ask this question is because I have been told that I dont necessary have to have a specific one and some people tell me that the one for it is the Holybro PM07, if someone out there can help with these questions I would very much appreciate it

Regards
Mark