The Planet Coruscant in the Star Wars Galaxy is close to the deep core of the galaxy. So how likely would the planet fall into the supermassive black hole at the centre of the galaxy?
Not very likely because that's not how gravity works - a black hole doesn't actually "suck" objects in unless those objects happen to get really close to it.
A good reference is here: Can a planet orbit a black hole?
Now to actually get sucked into the black hole, it has to get incredibly close because, I think as I said a bit earlier, if you're far away from a black hole it just behaves like a star - the gravity just obeys the normal laws. If you want to actually get sucked into the black hole, you have to get pretty close and black holes are quite small, so the chances of that happening are, actually, pretty rare.