The Ghost wins if he ever gets a shot. As a spot, he gives you the break and ball in hand after the break. Rack for nine ball and break. You only win by running out. The Ghost wins the rack if you don't run out. A scratch on the break loses.
We used to play a scored version, playing 10 racks. One point per ball and two for the nine ball. Max score was 100.
I think most players should do the progressive ghost:
After the break, remove balls from the table until your current number remains on the table. Take ball in hand and try to run out.
If you beat The Ghost in a race to five, increase your number -- the number of balls you have to run for a win -- by one. If you lose, you have to decrease your number. Make the race longer if you prefer.
If you beat the nine ball ghost, the next step is to play the 10-ball ghost, then 11, then ... After the 10 ball rack, either rack 15 or figure out where to place the additional balls.
Other points:
"Pro Ghost" does not give up ball in hand after the break. You need to learn to play position on the one ball.
The Ghost has a FargoRate that depends on the table. If you are even with The Ghost on your home 8-foot table with the expansive pockets, The Ghost on that table has your FargoRate. If you try The Ghost on the front 9-foot table in the pool hall with the tiny (one pocket) pockets, and The Ghost beats you 10-5, The Ghost's FR on that table is 100 points over yours. (That's based on the standard FR calculation from ratio of wins.)
If the point of the exercise is to learn to run out, I think versions that allow safety play are counterproductive. Find ways to run out. Play position on banks. Learn to kick to make the ball. Learn combos and caroms. Make a ball; don't be afraid and hide.