'ps ux | grep programname' will filter the list for only what you want to find.
-9 is basically the "force termination" signal, the one that bypasses all efforts to safely shut down the process. You should only use it when nothing else works.
Have a look at the killall and pkill commands, both of which can kill processes by name. They can be a bit dangerous though if you have multiple processes with the same name.
Read these manpages for more:
man 7 signal
Edit: this page has a simple rundown on Unix signals: