8.0 and 9.0 are updates from 7.0 as i see it.
So 8.0 or 9.0 would be better. 9.0 has support for USB whereas 8.0 does not (without adding it which requires some knowing about Linux to do).
You can download Linux...
8.0 and 9.0 have a boot mamger/laoder which you can choose you to install.