These individuals were working part time because their hours had been cut back or because they were unable to find a full-time job.
Part time employment increased 600,000 people in September?
This isn't all that surprising, given the ramp-up to Halloween, Thanksgiving and Christmas - and many corporations (like Toys-R-Us) were trumpeting how they planned to increase their part-time rolls by tens of thousands of workers. Toys-R-Us alone was something like 50,000. Then start figuring in all the other department and big-box chains out there and it's easy to see how employment can be ramped up VERY quickly.
The real BS there is how BLS admits that it's counting people who have more than one job TWICE (see my emphasis/bold above). So if, say, your full-time employer cut you back to 32 hours and you decided to pick up another 8-10 hour job to make ends meet you actually helped REDUCE the unemployment rate. Because you now have TWO jobs.
AEI has a really great analysis on the situation that ties all the pieces together pretty well. Worth the read, AND deserves to be posted on any/every thread dealing with the economy and jobs.