The 2009 Jaguar XK has plenty of standard safety gear, along with a sturdy and sophisticated yet lightweight aluminum structure that would otherwise indicate good occupant protection; but with a lack of crash-test results (as is commonly the case for more expensive sports cars), we can’t say that for sure.
Kelley Blue Book lists four-wheel disc brakes with four-channel anti-lock braking system (ABS), Trac Dynamic Stability Control (TracDSC), anti-theft security system with engine immobilizer, and "Jaguar's dynamic head restraint system that helps prevent whiplash in case of a rear impact" as other safety features.
Edmunds points out that "all XK convertibles have two aluminum hoops that auto-deploy in the case of a rollover accident." Cars.com makes note of the alert system called Forward Alert, which “sounds a warning if the car is approaching an obstacle at too high a speed. The driver can preset the distance at which the alert activates."
J.D. Power also gives an extensive list of the 2009 Jaguar XK's safety measures, including "dual front airbags" and "seat-mounted, side-impact airbags for head/chest protection for front occupants," but does note that the National Highway Traffic Safety Administration (NHTSA) has not crash tested the vehicle.
According to Consumer Guide, "Available safety features include ABS, traction control, antiskid system, and front side airbags that provide head and torso protection."