If they were OK in your garage last winter, you should be fine doing that again. Planting success outside, in your zone, has a lot to do with the particular micro-climate. I know that some people on this forum are successful in zone 8a. If you plant close to a south facing wall, heat will radiate off the wall at night. Plant the bulb so the neck is just at ground level, and mulch. If frost is extended a frost blanket would also help. I would wait until the spring to try planting them outside to give them a whole summer to settle in. In your garage, the plants may or may not go completely dormant. Dormancy results from a combination of reduced day length, temperature and moisture. Blooming is a result of increasing day length, temperature and moisture. Next year's buds have already formed deep inside and are waiting to appear next spring. If you are not trying to force blooms early, and are willing to let the plants "follow their own calendar", I don't see why they wouldn't bloom next year. Just be careful about keeping the soil too wet: rotting diseases love cool wet soil.
for the great info. I'll keep them in the garage and plant them in the ground in the spring. I do have a south facing border close to the house that should be perfect. I wonder whether I should be concerned about voles. I've had amaryllis bulbs vanish in the past. 
I need to clean up my large overgrown back border to check on the progress or disappearance of bulbs previously planted. 
