If a number x is something more than another number y, it means that you can obtain x by adding something to y.
So, if we want to get 4 more than -9, it means that we must add 4 to -9: the number you're looking for is
On a number line, bigger numbers lie on the right, so if you start from -9 you should take 4 steps to the right, and you'll land on a number which is 4 more than -9.