sabresword, I'm assuming you don't know at what temperature you fermented at? The instructions say it ferments best at 53-59F, but I'm assuming you fermented at room temperature. The instructions say the yeast is indeed a lager yeast (which generally perform better at the cooler temperatures), so it's quite reasonable that it finished so quickly (8 days is not actually very "quick" - try fermenting US-04 at 70-75 if you want to see "quick"!). That said, there are a few other factors here.
If your temperature didn't get too high (i.e., above 70 F), then you'll likely still end up with quite a nice beer. Next time, it would be better if you could keep it cooler (temperature control is the single most important thing in making beer), but for this batch, it should be fine.
The instructions say to rack the beer to secondary. This is old advice and is no longer necessary, unless you're planning to lager the beer at cool temperatures for several weeks/months.
The instructions also say to sprinkle the yeast on top of the wort and not rehydrate. This is also bad advice, as sprinkling dry can reduce yeast viability by up to 50%, and yeast cell count is particularly vital with lagers. You need A LOT of yeast cells to have a successful lager fermentation, and knocking off 50% of them right out of the gate is not a good practice.
So to summarize. For this time, your beer will probably be drinkable. For the future, to make better beer, make the following changes:
- Control fermentation temperatures (Google "swamp cooler" or "fermentation chamber" on this site, depending on your budget)
- Rehydrate the yeast before pitching
- Do the fermentation in primary for 3 weeks, and forget about the secondary. Lager it in the keg or bottles.
Hope this helps, welcome to the hobby!