Automate printing with options?
Let's split the problem into two parts: scaling and printing.

Scaling

You can scale a PDF on the command line. Consider creating a temporary, scaled, PDF to print. 

See scaling PDF content and page dimensions from command line for suggested approaches to this. The highest voted answer suggests using cpdf with a command like:

cpdf -scale-page "1.1 1.1" in.pdf -o out.pdf


An alternative tool is sips. This tool is included with OS X and is surprisingly capable.

Printing

As you have discovered, OS X's printing system is the Common Unix Printing System (CUPS). CUPS includes the command line tool lpr which can accept all the settings and options you need.

For printing the PDF via the command line see:


Print PDF from Command Line – cups-pdf, lpr -P PDF
CUPS printing of pdf files


To list the available printers, use:

lpstat -p -d


To print a PDF file to the default printer, use:

lpr file.pdf