Yes, it is possible. 0.009" = 228 $\mu$m is about 20x larger than the wavelength of your (I'm assuming) CO2 laser. So. In theory, you can focus much tighter.
There are some practical issues however. I am not at all familiar with the specifics of laser-cutting tools, but here are some general things to think about:
To focus tighter, you need a higher numerical aperture (NA) with a relatively clean, well-behaved laser beam. If you have laser light coming into your lens from all directions, it won't focus nicely. If your beam is well collimated, even if the profile looks nasty, then you can focus well. If you have a lot of diffuse scattering, etc, you can clean up the collimation by using a spatial filter at the expense of laser power.
The next step is to improve your NA. This basically means getting a lens with a shorter focal length. If you aren't utilizing the entire diameter of your lens, you can also improve your focus by expanding the beam size with a telescope (made from two ZnSe lenses) before focusing it (counterintuitively, this will make your focus spot smaller). This is probably more trouble than it's worth unless you already have big optics and a small beam diameter, although since your beam is relatively small, you might consider this.
Issues with using a lens with a smaller focal length include:
(A) Shorter working distance (distance between lens and target surface). To dramatically reduce spot size, you'll have to go with working distances in the millimeter range. If all you're looking for is a factor of 2, then basically your spot size will scale with focal length. I'm not sure if this will work in your tool, but if you can bring the surface in close, then definitely try it.
(B) Lens damage. With a really tight focusing lens, the beam begins to significantly focus before it leaves the lens material. If the intensity of the light increases beyond the lens damage threshold, you'll obviously have problems. Whether this will be an issue depends on the details of your setup. You might mitigate this problem by using a plano-convex lens "backward" (with curved side toward the focus), but it may not be necessary, and this will add aberration.
(C) Thickness of lens. The shorter the focal length, the thicker the lens. This may be a (minor) problem if the lens mount of your tool is incompatible.
Additionally, you want to make sure that there are no other aberrations in the focus due to misalignment or spherical aberration. I recommend going with an aspherical lens if you're trying for a tight focus.
Finally, depending on how nicely your material cuts, a tighter focus might be a moot point. If the cut edge roughness is on the order of the laser focus width, then reducing your focus won't give you a narrower line anyhow.
Hope this helps!