Find a good kicking system to start with.  There are plenty of them out there (like the mirror system) that make it easy to find the geometric kicking/banking aim point.  That will help you at least get a hit most of the time when you are hooked, and it's also a good way to learn how english and speed affect kicks and banks.  With a good stroke and a lot of practice, you will eventually be hitting virtually everything, and you will be 1/2 ball accurate on most easy kicks.  At that point your kicking skills will be in the high B or low A range.  Going beyond that requires an excellent stroke and more time and effort than most people are willing to put into it, but you can find more help here once you get to that point.
Regarding safety play, I would recommend first finding a good system for 2 and 3 rail kicks.  The spot on the wall system, for example, is super easy and fairly accurate once you learn how to apply it.  Being able to hit the OB very thinly and drive the cueball 2 or 3 cushions to a safe spot is one of the biggest defensive shots in 9-ball.  It is heavily used, but hard to hit perfectly if you are hiding behind only one or two balls.  Having a good 2/3 rail system will get you in the neighborhood on these types of safety shots.  Really, if you can hit thin-ball safeties pretty good, and you can bank balls straight back and lay them on the short rail, you have a pretty good start on 9-ball defense.  In 9-ball you only have to cover one ball, so the hardest things are learning when you duck and when to shoot, and protecting against the easy jump shot (closer is better, frozen is best).
Good luck,
Aaron