The nine hole course I operated had nearly as much bent grass to tend to as the local 18 hole country club in town. As TD mentioned, you still have to own all the maintenance equipment and those expenses certainly don't get cut in half with 9 holes as opposed to 18.
In most larger metro areas, the food and beverage area can help support the golf operations. Numbers of potential customers are on the club's side. In smaller markets, it doesn't neccessarily work out that way. Some clubs will use the F&B as an excuse to build larger clubhouses only to realize the economics don't work out and the debt becomes too much to handle.
Too many private clubs reach an unfortunate demise when they depend on F&B to save the day.
Ken