@TheGodEmperor
I don't know about yuri or not, but from what I have seen, her maid is showing way more familial/caretaker love than any sorts of romantic one at all.
I would say it is more adoration than anything else. Otherwise she would have been the one who reacted badly from the thought of being separated with her master when she goes to the academy.
Ofc that isn't going to be the ultimate proof of the relationship being platonic, but I have yet to see any sorts of romantic leaning from her. Adoration and familial love? Yes. Romantic love? No.
Not discarding it though considering that the novel has the "shoujo ai subplot" tag I don't think it is that unlikely, just that they are too young currently to judge and the signs are so far something you could more easily interpret as familial love. (Blushing is not a telltale sign of romantic love)