Kinda thinking it's your ssd from the symptoms. My first thought was RAM but 9 hours is plenty of time . Try installing the OS on one of your extra HDD's and see what it does. (seems the next best step)
While your at it i would check all your sata cables, try a different sata port too. Might be a bad cable or port.
If you get the same issue, try booting from 1 stick of RAM and switch them out (bad RAM doesn't always show errors in memtest)