Looks like you can’t:
“No Dell AIO 900 series printers can be used with Macs. To save money on the components, these printers were built using low capability chips that offload almost all processing to the host computer. The procedure is completely proprietary to this branch of printers and no driver is available for any other OS than Windows.
The printer is basically a Lexmark with a Dell logo on it, but drivers for the comparable Lexmark printers have been confirmed not work. You cannot use the “Generic” or “PostScript” drivers with this printer either. Its hopeless.”
http://www.fixya.com/support/t1543471-dell_photo_924_mac_os_x
Your could probably look into a virtualization software to run run windows on a mac. THe only one I know of is vmware fusion but it’s not free.
Good luck.