Hi,
To respond to the OPs PM -
The Arduino is easily able to read 9 channels of RC Input from an RC receiver and also to generate 9 Channels of servo/esc signals.
RC Receiver -> Arduino -> RC Servos and ESCs = No Problem
The usual approach to generating a servo signal is to use the Arduino Servo library, its a well known, well used library which is very good at what it does, which is this bit -
Arduino -> RC Servos and ESCs
Internally the servo library uses a resource of the Arduino - Timer1 - which the servo library assumes it has full control of.
The library you linked also uses this same timer but in a way which is not compatible with the Servo library, this will cause you a problem.
What I have proposed to you is a library that reads incoming and generates outgoing RC Signals without you having to worry about timers and things.
Other than that, what you want to do is definitely possible but before anyone recommends you go out and buy all the hardware what else do you plan for the project ? is it just to add a fail safe, if so Arduino seems a bit over the top ?
Duane B