It has been my experience that Russian tortoises prefer the broad-leafed weeds and plants to the exclusion of blade-type grasses. However, I have seen them nibbling on new grass shoots, so maybe they would eat the wheat grass as it comes up out of the ground, but not after it gets a bit older (the plant, not the tortoise).
I grow it and feed it daily to my big Sulcata. I see no harm in feeding it to your Russian, however, they prefer broadleaf weeds and those are a better diet for them than grass...