Hi There,
the Daily Quest "Complete Valhalla Rank Greater than 9" seems to be buggy.
I just completed Rank 10 (also 9, 11, and so on). The Achievement "Road to Valhalla II - Complete Trials of Valhalla rank 9" was activated but the Daily Quest is still open.
Any Ideas?

I do not have the answer for you, but someone else may. If no one here has the answer, you can contact support buy clicking the "Support" tab at the top of this page. There may be a bug in the game. If you do end up contacting support, please update this posting with the solution or let us know what support said.