should/ or could I install smart sdr on my computer before I get my radio

Yes you can, but you can't do much with it until your 6x00 rig arrives. It isn't like PowerSDR that has a "Demo" mode. Since all the processing is in the radio, you can't "test it out" without the radio. It only takes about 20-30 minutes to get it going once the rig arrives. But in the mean time, if you install the software early, you can begin planning which virtual serial ports you want SmartSDR CAT to assign, how you want to set up DDUtil, and you can read the manuals and installation guides. Time well spent!