9. (10 points) On a plane, there are 5 different lines, and these 5 lines form $n$ intersection points. How many different values can $n$ have?

保留源文本的换行和格式，翻译结果如下：

9. (10 points) On a plane, there are 5 different lines, and these 5 lines form $n$ intersection points. How many different values can $n$ have?
【Analysis】According to the problem, we can classify and discuss, and finally determine the value of $n$.
【Solution】Solution: According to the analysis, $n=0$, which means 5 lines are parallel to each other; $n=1$, which means five lines intersect at one point;
$n=2,3$ do not exist;
For $n=4,5,6,7,8,9,10$, the situations are shown in the following figures: there are 9 different values for $n$, so the answer is: 9.