I'm wondering if it's possible to dig up and move an 8' pine tree?

No

Cerainally nurseries move trees this size all the time.

We harvested 5- 5 foot wild native pine trees before new home construction and 50% lived. The secret is to get a big root ball keep it intact with movement and transfer with as many roots as possible. Some roots shoots can trail several feet outwards. Spring or Fall planting would be recommended. We actually had better luck doing this —than buying nursery stock that soon failed the first year in the ground.

http://homeguides.sfgate.com/transplant-wild-pine-trees-44035.html

Hi Jackie, I believe you could move a tree that large but you need heavy equipment for the job. You certainly need to dig out a very large root ball. Very large. There are companies that you could hire for this kind of job. Best wishes.

i have had very good luck with moving them but only in the fall when they continue to draw the moisture thru the winter and spring