1. You wrote: The liturgical books I have are a gift to me from an Orthodox source. Does this include the fourteen-volume Menaion? Or, at least, for the purposes of this discussion, the volume for December, which would have the services of the Conception of the Mother of God appointed for December 9?
2. If you do have the text for this feast in your liturgical books, it would help immensely if you could post the text for Vespers and Matins for this feast. If scanning to text form is too time-consuming for you, most scanners allow for a page to be scanned and saved as a PDF or JPEG file, which can then be uploaded to the forum. Then, it would be possible to compare the text I have already posted, with what you have. That's only fair and reasonable, don't you agree?
3. If you do not have a Menaion, then it should be possible for you to photocopy the relevant pages from your church's Menaion (or, ask your choirmaster/choirmistress to do it for you), which can then be scanned and uploaded as I described above.
I can also confirm that the writer of the Canon at Matins is St Andrew of Crete, and the writer of the last hymn at Lord, I have cried is St Germanus of Constantinople, both contemporaries of St John of Damascus (late 7th-early to mid-8th C). So this feast is definitely pre-schism by a long shot, and the bulk of the hymnography written by a man who knew his onions when it came to the Mother of God. I've also found out that St Germanus was hardly ignorant about the Mother of God either - he wrote a number of discourses on various feasts of the Mother of God, as well as good amounts of hymnography for her feasts as well as for various saints.