can you disable the crosshair in the options menu?

Not that I know of.

On PC it's right in the Options>Gameplay Menu in with the Difficulty Slider, subtitle options, etc. I don't see why it should be different for XBox, but I don't know for sure since I don't own one.

I guess it would be like in on the pc, not sure though, never even given it a thought.

EDIT yeah it is under gameplay in the options menu