One of the advantages of ultra-low profile RAM is that you can put a fan over it. I don't have that D9 mounted, so I can't tell you if it would fit, but you can try it yourself. The other thing you can try is to put a fan in pull configuration. And you can have one in push, one in pull, and nothing in the middle.
As for the lost mb screw, I have been known to pick up a case and tilt it until the screw is gettable. You can get a magnetic tipped screwdriver for such things. I scouted around locally and found a Phillips head #1 with an eight-inch shank to help me with deep cases.
Did your case cost a lot? Sometimes it is better to buy a new case and start over.
In any 'case,' good luck.