A9CAD appears to be a 2D CAD drawing program, whereas FreeCAD is centered around 3D parametric modeling. They're different approaches to creating things.
If you want a decent free 2D drawing package, try DraftSight, Or LibreCAD if you want open source.
If you want a decent free 2D drawing package, try DraftSight, Or LibreCAD if you want open source.