There is no extradition treaty between Saudi and us so wouldn't be a certainty. diplomatically, could be done, it depends on what their tinpot league is worth to them.
I can’t see Saudi wanting him tbh. It’s becoming increasingly obvious that the raison d’etre of the Saudi league is to circumvent FFP and sign big players on big wages to loan back to Newcastle, ergo if he will tarnish Newcastle’s image then he is not worth anything to them.