A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data
=LET(b,IF(WEEKDAY(A2,2)=6,INT(A2)-6/24,IF(WEEKDAY(A2,2)=7,INT(A2)-30/24,IF(A2-INT(A2)<9/24,INT(A2)+9/24,IF(A2-INT(A2)>18/24,INT(A2)+18/24,A2)))),
a,IF(WEEKDAY(B2,2)=6,INT(B2)-6/24,IF(WEEKDAY(B2,2)=7,INT(B2)-30/24,IF(B2-INT(B2)<9/24,INT(B2)+9/24,IF(B2-INT(B2)>18/24,INT(B2)+18/24,B2)))),
MAX(0,18/24-MAX(9/24,(b-INT(b))))*24+MAX(0,(MAX(9/24,(a-INT(a))))-9/24)*24+(NETWORKDAYS(b,a)-2)*9)