Stella,
I don't think you can get higher resolution static data by running WRF. Even if you run WRF at higher resolution, the static data is still derived from your input data and then interpolated to WRF grids. As shown in your example, the 500m-resolution input data will be interpolated to 90-m WRF grids, but this doesn't mean that you can have 90-m resolution static data from WRF.