Do you get any error/status messages in the dash display while trying to start? If the key fob is not detected while trying to start, the 2009s (and I assume later Genesis models) will display "Key is not in vehicle" or "Key is not detected." A test you can try: unlock the car normally, then leave both fobs outside the vehicle - say 10 or more feet away. Try starting. It won't start but you should see some sort of message about the fob not being detected.
If either error message appears while trying to start while you have the fobs outside the car but the same messages do not appear when trying to start with the fobs in the car that indicates the car-to-fob communications are working and your bug is something else. In theory, an error message will display if you try to start the car with the shift lever not in Park or Neutral... a common failure on many automatic transmission cars though is for the "Park/Neutral Safety Switch" to fail or be loose so it fails to detect a shift lever in Park or Neutral. That prevents the vehicle from starting. Wiggling shift levers, shoving them firmly against the Park stop, or just trying Neutral instead of Park, helps such cars.
The theft alarm imobilizer function disables the starter if the car thinks the alarm went off. Does your car start properly if you just close the doors without locking them - i.e. parking the car without arming the alarm? Try this test: next time it won't start, push the START button twice so the dash is lit up as though the car were started. Slip the fob into the dash slot... Wait for 30 seconds or more, doing nothing... THEN try starting. If it starts on the first try, the alarm/imobilizer was triggered for whatever reason. On the underside of the hood there should be a few rubber bumpers. One is along the driver side edge of the hood, about half way between the windshield and front lip of the hood. This pushes on a button in the black plastic stuff around the engine - this is the "hood open" switch that feeds the alarm. It was common for this rubber bumper to be missing, especially on the 2009s. Without it, or if it is worn, loose, or screwed into the hood too far, any vibration in the car/hood may trigger this switch, tripping the alarm. There are other posts on this site describing this rubber pad/bumper and likely a photo or two as well.
If none of that applies to your situation, post back with details on what you do see and don't see. "It is acting like there is no fob present" should generate those error messages I mentioned... if you don't see such messages, what do you see or hear? Anything on the dash light up for example? Is the steering
wheel solidly locked? Sometimes turning it a little, away from the locking pin, helps folks.
mike c.