In photoshop cc try File>Automate>PDF Presentation
What version of photoshop elements do you have?
In some older versions there is a workaround way to save multi-page pdfs.
Thanks. Does creating a "Pdf Presentation" reduce the resolution/quality of the images? In other words if I create this 2-page PDF Presentation file as you described and have it printed, would it the the same quality as if I took the same two "Photoshop PDF" files I created in Photoshop Elements 12 (that's the version I have) and had them print "file 1" on the front and "file 2" on the back (separately...would have to run through printer twice)? I ask because when I used Preview to combine 2 pdfs into 1, the one resulting file was something like 5x smaller than either of the individual files was by itself...so I know something was lost in that process. Thanks again for your response.
You should talk to the print vendor and get their file preparation requirements. They may want to use a special paper and document size to get the 9-up to print to include bleed and the ability to trim out the 9 cards without misalignments. Technically, you would send them 2 CMYK Photoshop PDF files @ whatever resolution they require. So, consult with them, then you will have more information to help you move forward.
Also, keep in mind most offset print machines require an area known as "gripper" that has to be included in the document size.
Does creating a "Pdf Presentation" reduce the resolution/quality of the images?
That depends on how you set it up. When you choose Multi-Page Document and click Save on the initial PDF Presentation dialog box, another dialog box pops up called Save Adobe PDF. These are all of the options that determine the color, resolution, etc. of the PDF presentation. It looks complicated, but usually you only have to choose a preset that fits the kind of output you need and then you're done. There are low resolution presets for screen viewing, high resolution presets for printing on desktop printers, printing presses, etc.
You need to ask the print shop if there is a PDF preset they would recommend that you choose. Because PDF is a widely used format in print shops, many of them can either tell you which PDF preset to choose to preserve the most quality on their equipment, or they will send you a preset they created for their shop and ask you to install it and then choose that from the Adobe PDF Preset menu at the top. You'll see that Photoshop already has a number of built-in presets for the PDF/X commercial printing standard, but you won't know which version to choose (PDF/X-1a? PDF/X-4?) until you ask the print shop which one they use.
Apple Preview also has a way to generate PDF-X files, but it isn't as straightforward. A print shop will typically prefer a PDF generated directly from Adobe software.