Formula to include “blank” if cell =0

I worked out most of this but cannot get the last part which would require the cell to be showing “0” if another cell is blank. Here is what I tried most recently. This is in Google Sheets, in case it matters.

=IF(B11>9.5,B11*0,IF(B11<9.5,B11+20-B11,IF(ISBLANK(B11),"",B11)))