Fixed shakiness, now dead alternator?

[dwd1985]

So I had 2 bad coil packs, and my car sat in pieces for about a week while I diagnosed the problem and waited for my parts. This included the battery and alternator being removed and re-installed about 3 times each. After every time I would re-install it, my battery light would come on only when the keys werent in the ignition. But it wasnt a big deal. As of yesterday, I got my coil packs, fixed the problem, and stopped caring. However, the battery light remained on. My alternator belt was slightly loose, but I was planning to go back in there and tighten it today. It wasnt too bad though, just enough that if you floored it or took a really hard corner, you would hear it squeak. But I didnt think much of it. So it drove fine all last night and all of today, until I noticed it started taking an extra couple of seconds. Then my radio started to turn itself off while driving, and then my ABS and Airbag lights both came on. Next time that I tried to re-start, all I got was the relay click. I took out the battery and alternator again, looked everything over, re-assembled it, tightened the alternatore belt really well, and still, nothing. I had enough power for the electronics in the car to work, but not start. This is obvsiouly a dead alternator and/or battery, but they were both just replaced only 9 months ago! This is pissing me off, I only had it back for a day before it broke again. Anyone have any idea how this happened to a mostly new battery and alternator? I am taking my alternator to Autozone to have them bench test it in alittle bit. If its bad, ill get a new alternator. If its good, a new battery. But any ideas how I possibly did this? I know I broke it myself, there is no other explanation for it.