[ubuntu] is ubunti for me?

tools are available for Ubutnu as well. it's just that they are setup and preinstalled on Kali. Kali also uses a different keel to Debian's i believe. Otherwise commands for ruing the system are the same. you can look at Backbox Linux if you want an OS like Kali but based on Ubuntu.

i would start with literature on how system and networking actually work, how security Works etc. only then i would dive into scripts, mathematics, probabilities and such. usings scripts is easy (so called "script kiddies" do it all the time), it's understanding them and modyfying them that is a bit harder.