In the meantime I also updatet to Alpha 3 and really battery life in my Epic seems at least two times better.
But this <Unfortunately, Clock has stopped> error remains.
Furthermore, so I think, Alpha 3 is not as stable as Alpha 2. Perhaps it remained a rest of CM7 code which sometimes forces my SPH-D700 CM9 Alpha 3 to cascades of lights and crashes.
I haven't done a factory reset when I started with CM9 but wiped all that other items mentioned.
Living in Mexico I payed a lot of money for activating my Epic with the operator IUSACELL/UNEFON (NEXTEL has coverage only in the upper north and in Mexico-City). So I fear to loose my personal configuration which I got times ago in a service department of IUSACELL.
Alpha 4 will be achievable soon. So I'll stay on CM9: "The better is the enemy of the good!"