Your best bet would be to buy a copy of VMWare Fusion or Parallels Desktop and install a copy of Windows under that. Those are Virtual Machine programs that can allocate some of your resources from MacOS to the "virtual computer" that will run Windows simultaneously.
My personal preference is for VMWare over Parallels (though Parallels is priced less I believe)... I've never had any problems using a USB to Serial adapter with my Uniden BC250D or the USB cable for my GRE PSR-500, with Windows 7 Home Premium under VMWare Fusion.
The problem with MacOS is that there is no universal or easy way to connect or communicate with all of the different scanner models (not all USB to serial adapters are reliable, and proprietary cables don't have Mac driver support), and no one has dedicated the time or effort to developing a good scanner programming/control program for one scanner model, much less all the different models that exist.
Currently using Parallels, with little problem. The RS scanner programming cable works well. I also have a Prolific serial adaptor that works.
I can perform all the functions I need, to program and control the RS and Uniden scanners.
It is a bit of a pain to initially set up. Been a Mac guy for 10 years. When I had to install Windozs on my Mac it did hurt a little.