I use a rectangle type projection with my work, for 3d laser imaging. basically you use scanlines just like a tv in a square. the optics are very expensive.
A cheap way to do it would just to use a bare diode with the right lense. The diode would emit a line and then you could a beam expander type optic to open the line up into a rectangle. the beam expander is adjustable so you could make it smaller or larger to suit. 9x24 is kinda large but anything over about 5mw should be visible at night.