Congrats
It's a great feeling isn't it....but doing it once is lucky but do it 2-3 more times and you know you game has stepped up. Just keep in mind that's there's always a factor of luck playing 9 ball because any ball you pocket in any pocket keeps you at the table.....so slop counts which it's supposed to since 9 ball is a gambler's game.
Try playing 10 ball where the rules do not allow for slop or better yet, straight pool where you have to even call shots that will carom off another object ball into the pocket....zero slop in straight pool. Your overall progress will be more accurately measured because every 9 baller knows there's days when the luck is with you or it's against you.....it's just that way.....you shoot the 6 ball at the pocket and it misses and bounces off a rail or some other object ball and it goes into a different pocket than the one you meant to play it in...or the one rail bank shot you play to the side pocket that became a double bank shot that went into the opposite side pocket but you keep shooting because it's 9 ball and everything or anything that goes into any pocket counts for you.
Nonetheless, there's an artfulness to seeing a 9 ball table run out without any slop (especially on 9' table because doing it on a 7' is just too easy) and observe someone use great center table cue ball position play. It's beautiful to watch when that happens but 9 ball is basically a gambler's game because anyone can win and it just takes a little bit of bad luck from your opponent or your good luck that the shots kept going in.....any pocket.
I like 9 ball when I play strong opponents because I can always get lucky if I don't have a shot or have become bored with safety play. At any time, I can just pound any object ball or any object ball cluster and just root for something to drop. It's not the smartest way to play but in 9 ball luck really does matter more than in 10 ball or straight pool.
Enjoy the moment and now make it count......see how many racks it takes to do it again or how many more you times you run the table it in a month........hopefully, it's not going to be another 20 years.