How to build an additional concrete/cinder block wall in basement, where the crawl space and basement meet
First I'd provide a 22" wide by 12" thick footing.


Throw (3) continuous #4 bars in there elevated 3" clear from the bottom surface of the footing. They should be spaced 4 1/2" apart from one another and the group of 3 should be centered in the footing. 
Install #4 L shaped dowels (approximately 6"x3'-0") sticking out of the top of the concrete footing at 48" on center . Tie the shorter length of these to the continuous bars mentioned in step 1 to keep them in place when pouring the concrete. Alternate the direction (left and right) of the shorter length of the L. 


Then I'd construct a 8" CMU wall.


Place an additional #4 straight bar in the cells the contain the dowels. Footing should already be poured.
Vertical grouting at 48" on center. (grout the cells of the CMU that have the rebar)