I'm from the Netherlands and its an option that's quite common for companies that have 36 hour work weeks; 1) take Friday afternoon off (or Wednesday if you're children are off from school) 2) have a full day off once every other week, 3) have an extra day off every week but work 9 hours the other four.

Personally 9 hours per day wouldn't work, after a solid day of programming I tend to loose focus too much after about 7 hours, but some of the alternatives work fine.