OK, everything is done now. Server and ISPConfig are working now. Just had time today for to do the finished install! Also, Softaculous is installed and working now too! With some problems upfront! One of that problems was, that Soap wasn't installed and Softaculous need Soap for to run. Same applies for IonCube Loader. Beside of that, there some problems with some PHP Scripts, which couldn't work. That's because in using the tutorial for Minimal Server and Debian 9, there only PHP 7 installed. I came across that while trying to install XCloner, which ended up in just a blank screen. The support from Softaculous is now working on to solve that by changing something in the script. And similar will maybe in some more scripts.