It doesn't make a difference if you are just starting out in pool. Both games are fun and can be played competitively, but the 9-ball game offers more winning chances. It is important to think about your own style and your game skill to decide which of the two you prefer.
Playing 8 ball is great for beginners or those who just want to have fun. You'll have more chances to hit the ball and the game will be easier than 9 balls. This game is more complex than one you might have played before. All the rules must be understood, such as how to place pocket balls in numerical order. Also, you need to know how to shoot certain balls.
With regard to the 8 ball you need to know how to make a play, when to put it in a pocket and when to let it go. To make a run out you'll need to first pocket the balls on your team, and then take the 8 ball. You may need to make several pocket shots depending on which tournament you are playing in before you run out. However, you should be able hit the 8 ball in as little as one shot.
There are many similarities in 8 ball and 9 ball. You can either use a triangle to direct the balls to the correct spot or play with slop. However, you cannot pocket any ball on a 9 ball. You have only a few chances to make 9 ball shots, and the only one that counts is the "Golden Break," which will give you the win, regardless how many of your balls were used.
The Golden Break is a shot you can make right after your break. You can win the game if you hit the shot. However, you will need to have good feel for the cue ball, or you may be in for a rude awakening. If you don't, it will be difficult to make the 8 ball. While the rules for 8-ball will vary, in general you need to be exact with your shots. This game isn't as forgiving as you might think.
The main difference is that 8 and 9 balls are slightly more challenging to learn. It is however more difficult to master. In fact, there are many different national bodies that govern the rules of 8 ball, and if you are unfamiliar with them, you will have to read up on them before playing. Keep in mind, however, that 8 ball rules are slightly different than 9 ball.