google sheets – Help with Getting the Difference of two dates or displaying NA in cell if no date entered

I am trying to Fetch the difference between two dates in different cells, or if the first cell is empty display nothing.

=DATEDIF(E9,H3, "D")OR(ISBLANK(E8))
Is what i have been playing with but i keep getting an error
if i simply use =DATEDIF(E9,H3, "D") the cell returns a very high number