I've added a temporary setting (I hope to remove the setting and make it permanently on) to turn on the conversion of abc (romaji) input into kana as the user types into fill-in-the-blank answers in the quizzing. It should work for all vocab questions and reading questions on kanji characters.
If you go to Settings -> Quizzing, you should see it just above the keyboard shortcuts.
This is in testing, so I'd love to hear if anyone has any problems with it, if it works, or anything else! If you do have problems, please mention the device/browser you are using, thanks.