getting those joins on your 9 patch or any straight intersection is easy peasy. make two 2-patches. 'nestle those seams together' nice and smooth to make into a 4-patch.
when you put it on the machine bed to run under the needle be sure the top seam (pressed to one side) is laying away from you(aka the seam allowance goes under the needle before the seam itself) and will need some gentle nudging with something pointy(bamboo skewer works nicely) to keep flat as it goes under the needle. the bottom seam that you cant see will be laying flat towards you and will follow along nicely all on its own, dont worry bout that one at all. the best way i can explain how this works is... the presser foot will hold the top fabric down as the feed dogs pull the bottom seam backwards pushing it into the upper fabric seam.
if it is done the other way the two pull apart as you sew, not good and rotten joins at the intersection. makes me so mad when that happens (never does now that i know the trick to it). you might need to turn the pieces over or around or some which way so you can sew the correct sides together but if you play with it i'm sure it will all become clear soon enough. ack, wish i had a pix of this somewhere. i'll search the net and post if i find one to look at. fingers crossed that helps your seam joins, j.