PostgreSQL not in path after installation
In contrary to other PostgreSQL installers (e.g. Homebrew), the EnterpriseDB installer doesn't install the PostgreSQL executables in a path covered by your default $PATH.

So either add it to your .bash_profile file

...
export PATH="/Library/PostgreSQL/9.6/bin:$PATH"
...


or

...
export PATH="$PATH:/Library/PostgreSQL/9.6/bin"
...


or symlink the executables to /usr/local/bin:

ln -s /Library/PostgreSQL/9.6/bin/* /usr/local/bin


You can't link them to /usr/bin/ because this path is protected by SIP and - after disabling SIP - a sudoer would have to prepend sudo  to link the files. /usr/local/bin is the default path for user installed executables anyway, so stay with this one.