There are 9 feet so it would usually be nine 12" pieces but since each cut takes away 1/8, you can only cut 8 pieces equal to 12 inches.
Considering this fact, each cut would take away 0.125 inches. If you're cutting 8 times, you would in all be taking away 1 inch.
So aside from the eight 12" sections, you would have a leftover of 11 inches.