=DATEDIF(C9,$F$1,"y") formula is in cell D9

=IF(D9=$H$6,4,IF(D9=$H$5,3,IF(D9=$H$4,2,IF(D9= $H$3,1,IF(D9<$H$3,0)))))
formula in cell E9




The above formulas work fine as long as there is a date in cell C9. If the
cell C9 is blank I get a return of 107 in column D9 and 4 in column E9 which
I assume is correct. The solution I am looking for is: When C9 is blank I
want D9 to = 0 (zero) also making E9 = 0(zero). I though making all the cells
in C =F1 but column C is an input cell which removes the formula making the
cell blank if the entry is removed at a later date. In short, is it possible
to make a cell point to F1 as the default value if it is blank?