Nick's answer will do what you want, but this might be better:
public MeaningfulFunctionName()
{
}
private void button9_Click(object sender, EventArgs e)
{
MeaningfulFunctionName();
}
Better still: Abstract out an object model and put
MeaningfulFunctionName
in there. Doing this puts the functionality into unit testable code. If you have a more complex application (many screens) try looking for the MVP pattern on google.