If you want to make adjustments to the print out, such as change the staple side or another value of this sort, make sure 'Automatic' is not checked in the line below 'Duplex-Printing' area and ...

Options for the CF9001 include a 10-bin sorter, 10-bin staple sorter, automatic document feeder, 1,000-sheet paper cassette, and a duplex unit.