Hi macshine and all others that wanted to figure this one out,
This one plagued me as well and through 15 different threads giving old info that is no longer relevant I finally figued it out.
You need to create an 8.5x8.5 paper size. From Safari or most any program (except calendar) select print. In the printer options there is a pull down menu called "paper size". It's most likely already selected "US Leter". Select "Mange Custom Sizes" and create a new paper size. Call it whatever you want. Make the paper size 8.5in x 8.5in and hit okay.
What you are doing is tricking the progam with this option. If you made a 8.5 in wide by 11 tall paper size it would still set it up in landscape. When you select your new square option it throws it off and forces everything into a 8.5 inch wide page. Now go back to the paper size pull down menu and select US letter. Don't know why, but it now lays eveything out in portrait mode. You will need to select your square paper size first and then the US letter size everytime you want to print in portrait.
I hope this helps.