The acidity the pines add to the soil is a bad thing for hops to be sure. However the shade they provide is probably a good thing for several varieties depending on where you live. Under extensive shade I had great success with Goldings which were getting a similar amount of sun to what you described (they still get a decent amount of shade through a canopy of trees) but they won't grow above 3-6' high in full sun down here in MS (4 yr old plants).
You can combat the acid problem a couple ways. First always keep the pine straw raked up in the area, especially around the plants. Secondly when you plant the plants use dirt other than what's in the area as in dig it out and put some good top soil in the hole. Third you could treat the area with lime or whatever it is you treat acidic soil with.
Schlante & Good Luck,
"Perhaps wisdom for me is understanding how truely small I am, and that there is no smug self centered moment of clarity when there is so much more to learn" Anthony Bourdain