How to hide formula results until conditions are met
Solution 1:
You should be able to accomplish this with the IF function.
The format is
=IF(CONDITION, ValueIfTrue, ValueIfFalse)
So in your case, it may work to do:
=IF(ISBLANK($E9),(I8+E9-G9-H9),"")
ISBLANK() in excel is a built in function to check for what it states.
$ is included so if you move over to another column, it still reflects column E. However, don't do that on the number, as that would always reference that number only, rather than following down to E10, for example, if you copy the formula down the row.