Worse comes to worse, depower the radio completely for about 2 minutes.
Sangeans lately have some periodic, small glitches with their keyboard entry (i.e., hitting the power button and it goes up one channel, hitting the band button and it gives you the time, etc.), that is usually fixed via a cold reboot, i.e. removing ALL power and then resetting that way. I've done this with my PR-D5 and PR-D14.
It wouldn't hurt to try it if you haven't. I'm only suggesting this because it's possible that the 909X2 has similar keyboard recognition firmware.