We run a legacy system and would like to upgrade from CF ver.6.1MX to ver.9 - is this possible?

Unless you already own a version of CF9 this wont be possible. CF9 is end of life & support and you wont be able to obtain it from anywhere (legally).

CF11 is the current version. You can download the developer edition to test your system and see what changes would need to be made in order to get things working. It also has a code analyzer that can give you an idea of what areas will need updating due to changes or depreciation.