First, for an IPA, that recipe looks a little low on the late hop additions for flavor and aroma for modern US-style IPA.
Did you add the 1 oz of cascade as a dry hop called for in the recipe? Their recipe page has it listed on the same line with the yeast rather than the next line, and maybe you missed it; I know I missed it on the first read through. If that was omitted it would definitely have less hop notes, given that only half an ounce is used for late hopping in the boil.
On the sweetness and bitterness. Did you measure your final gravity? If your fermentation didn't quite finish out all the way, you might be somewhere in the 1.020 - 1.030 FG range, which is going to make it taste sweeter. Your final gravity should be less than 1.018 for that style.
Assuming the 9# from the recipe is liquid/syrup and not dried extract, I've calculated you should have had an OG around 1.075 and IBUs of 65 for a 5 gallon finished batch size. For an IPA, you want an IBU to Gravity Ratio (BU:GU) of .8 or so. That recipe is about .86, which is about right. (Noticed you said DME, aka DRY malt extract...if you used dry extract, you definitely added too much malt and not enough bittering hops; 9# dry in 5 gallons would bump it to 1.086 OG. Dry and liquid malt extract are NOT interchangeable 1-to-1)
Assuming you finished around 1.018, you should have a 7.7% beer. If you say it's only 7%, then perhaps you're fermentation didn't finish completely.
So in summary, the recipe is about right as far as bitterness goes, but light on flavor and aroma hops (especially if you forgot the dry hop cascades). If you used dry malt extract, you used too much for the amount of hops listed.