If a mage were to use a shape earth spell to erect a wall, would it have an astral barrier like natural earth? Or would it be like processed material?

it's still the same material, just moved around. I'd rule it a barrier in the normal sense (they can move through, just very slowly) for earth.

ah... shape earth. Although not "in thread" I would like to point out a fantastic use for this spell:

Hostile cars parked on earth, gravel ect. can be "blocked up". Move some earth for under the wheels to the center. That will represent a problem for any rigger. Unless, ofcourse, there is a competent mage in the car... or a big troll.