Haynboy8.......something for you to consider before using any adapters, each adapter will reduce 1db, so two connectors will bring the antenna down to 3db
IMHO, Whyyy's suggestion to change out the connectors is a better work around
There's no reason why it wouldn't, it's simply an antenna. As you say it would just be a matter of morning the 9x. I would just go ahead and buy the whole frsky module, it's way better than the stock 9x module, and then you won't need to modify anything.
It truly gives 3dB boost over original 2dB antenna - confirmed with RSSI feature of FrSky telemetry. Even though it is longer then stock antenna, still fits my Turnigy 9x styrofoam box, without removing antenna.