Are you sure the software does not need updating not the scanner? Go here and put in your serial to check for updates: https://www.silverfast.com/get_update/en.html
You can get that here: https://support.nikonusa.com/app/answers/detail/a_id/604/~/super-coolscan-ls8000-1.11-firmware-update
No they are not "dangerous" ...
OK yes very odd that the Mac download is for Windows, sorry about that. Unfortunately then you will have to borrow a PC from a friend and update the firmware that way. You can run windows on your Mac too using Bootcamp or a Paralles.