Bringing the vial up to room temperature isn't an absolute necessity. It exploded because of the sudden change in the internal pressure of the vial and the fact that there is some respiration by the yeast that is CO2. FOr future reference, after taking the vial out of the fridge, slowly crack it open to let the pressure equalize, close it tightly and drop it into your pants pocket. This will warm it up and, while you are working, help to mix the yeast into suspension. When it is near the correct pitching temperature, release pressure again, give it a violent shake and place it on the table to stabilize.
As for the quantity to use, I don't do 1 gallon batches of anything. I, also, used a dry Cote de Blanc yeast for the 4 gallons I'm fermenting as of Friday (plan to back sweeten with another gallon of juice with brown sugar and cinnamon after reaching terminal gravity on the 4 gallons. You may have pitched more yeast then needed, but I would presume that will make the cider finish a bit faster then anticipated and perhaps a lot drier than planned.
If you can't keep it in the dark, you can wrap a towel or an old t-shirt around it to cut the light, but I would suspect like beer and wine, you don't want it light struck if at all possible.