Is there a way to download TurboTax on iMAC?

Many Mac users use TurboTax. What you apparently need to do is to visit their web site and download the version that works with your installed operating system. If you need help with this, then you need to work with the TurboTax support people to do the installation.

I tried to download and it would not work using Safari. I ended up installing from the disc.

Good for you. Incidentally, Safari is sometimes problematic. When that occurs you can usually get it done using another browser such as Firefox.