I think I got it. It took a few hours and it's not the best solution, but it works.
There is a free IOS App called "Canon Print". Download it from the App Store to your iPhone, iPad, etc.
When you open the app, there are a few options and the one we have had problems with is correctable when you click on "Photo Print" ("Document Print" appears to always go to the bottom tray anyway, so it's easiest to just use AirPrint for documents).
After tapping on "Photo Print", you will see lists including "Recents" that will bring you to your camera roll. If your photo is not in there, you will first need to "Save" your photo from an eMail or Message (or wherever it exists) to your camera. Then, click on and "Select" as many photos as you want.
When you have all of your photos selected, you will see how many "Images" you have selected in the lower left and then you can click "Next" in the lower right.
Drum roll - here, finally, is the answer we have all been waiting for!!!
In the lower left, click on "Print Settings". You will see that the "Paper Size" currently points to the size that would be loaded in the upper tray of the MX922. Tap on "Paper Size" to change it to "Letter 8.5"x11" 22x28cm". Make sure there is a check mark to the left of it and then click the "<" in the upper left to go back to "Print Settings".
Next, change the "Media Type" to "Plain Paper" (if that's what you're using), then click on "<" again and then click on "< Back".
Now, you can finally "Print" (lower right) anything from your IOS device to the bottom tray.
I have noticed that once you set your Print Setttings (to "Letter" and "Plain Paper", or whatever else you're using) that you don't need to change it again - the app remembers this setting for next time.
Although it stinks not to be able to simply use Airprint and select the size from there, at least photos printed through this Canon Print App will provide as many paper size, quality and other options as possible.
Hopefully, this App will be the best answer for everyone!
