Those Rx and Tx bars on the bottom of the GCS are telemetry communication speeds and have nothing to do with the radio receiver configuration. The Tx bar will jump up for example when you save settings to the FC, the Rx bar is indicating that the FC is talking back to the computer and sending telemetry.
PPM stands for Pulse Position Modulation and PCM stands for Pulse Code Modulation and from what I understand this setting is referring to the way that the 9X is communicating with its radio module so I'm guessing that should be set to PPM.
You say, that your Rx and Tx are bound, which means you should be getting PWM (Pulse Width Modulation) signals on the 8 outputs on your Rx. You can verify that the outputs are working by connecting a servo or an ESC to them, moving Tx sticks should be reflected by something happening on the other side.
I can't say which Output maps to what stick or switch on the Tx (refer to the 9X manual I guess) but connecting Rx outputs 1 to 6 to FC inputs 1 to 6 is a safe bet, then run the Tx setup wizard in the GCS and let it figure out what channel maps to what function.
Try to get it to work and if you fail post a screenshot of the Input config page and your wireing, so we can spot possible mistakes.