Rob, hopefully you still have some of that beer bottled, because I'd like you to give it a try after about 8 weeks in the bottle and let me know what you think. Nine days in the fermentor and two weeks in the bottle is not enough time. The bitter taste will mellow quite a bit over time, and it could very well be that your beer is just green.
The bad flavor you descibe is "bitter aftertaste" (not woody, fruity, alcoholic or vinegary - which I would attribute to yeast and temp). The primary causes of bitter aftertaste are water and hops (I'm also eliminating astringency from tannins usually caused by overheating grains). Making your next batch with S-05 and bottled water will absolutely make a better beer, but I wouldn't rule out that the flavor may just be in the kit itself.
your liver and spleen
its always clear
for one more beer!