Why?
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[COMMENT DELETED]
Failure to see the obvious.
'Nuf said...
EDIT: Actually, I think it was a double purpose move - 1.) to drive the Queen away and 2.) to protect the h1 square with the Queen. However, it fails to Qh2#, like you pointed out.
Seems like a lost game to white anyway, even though they will be materially equal after 10.Qh3 Qxh3 11.gxh3 Rxh3 12.dxe5, and the White King is dangerously exposed, whereas Black can castle with 12...O-O-O and activate his rook to try to take control of the d-file. Suddenly, both Black rooks are active, and White's Rook seems useless.
All just speculation. So in the end, the checkmate might've been intentional =/