does the adobe pdf printer have the function of merging documents into one?

To put it another way, you cannot just buy the PDF Printer at all. You can buy Acrobat. Acrobat is an app like Reader, but it CAN join PDF files. It also of course includes the PDF printer. So you can print to PDF, and combine the results, but not in one step.

And if you are thinking of using the Adobe PDF PostScript printer driver (part of Adobe Acrobat DC)  to create a single PDF from multiple print jobs, no, that isn't a function of that printer driver. It can only convert the output of one print request into a single PDF file and does not have the ability to concatenate new PDF (from PostScript) onto an existing PDF file. Sorry!

          - Dov

No. You can use JavaScript to combine files prior to printing.

Printing a PDF using any PDF printer is known as "Refryng" and like refrying a filet Minong results in a poor quality result. 

Refrying PDF Files by PePressure

http://abracadabrapdf.net/file/Refrying_PDF.pdf

Refrying PDFs – the good, the bad and the ugly by Leonard Rosenthal

The Acrobat PDF printer is only  sold as part of Acrobat.

Acrobat includes tools to merge PDFs by page or file before and after pages.