Can coffee beans be roasted in an airfryer
I haven't tried it myself, but I'm pretty sure that it would work. In general the temperature you need is between a 150 and 300 degree celsius, but the best way to find out is to try and see what works best for you. There are plenty of sites explaining how to roast coffee beans at home, even with less "advanced" gear (popcorn makers, ....). 

There are a few things to be careful about: 
You are working at high temperatures and the airfryer is not built for roasting coffee, so you shouldn't leave the fryer alone!
You should be aware of the strong smell that roasting coffee produces, I'm not sure if the coffee smell/taste (and I'm not talking about a fresh ground coffee's aroma) will affect the taste of other food you plan to fry. And last but not least, this won't produce very good coffee, since you don't have much control of the whole process.

Try:
https://www.breworganic.com/Coffee/HowToRoast.htm
http://www.sweetmarias.com/instructions.php

Good luck!