Trying hard...well done ! I think you are correct about 1 and 14 across. If every other letter was there, it would be possible to get BREAD AND BUTTER LETTER, and I suppose it could be googled, to find out what it means. But the definition included in the clue is not clear, which was my point.
Google is jolly handy but we should need it to solve a crossword puzzle.
By the way, if you are referring to 9a, I think you there already !