I don't know how I forgot you had a 9 inch. The 8.5-inch rear is 1 inch loner than the 7.5-inch rear, so the driveshaft is 1 inch shorter. I don't know about the 9 inch.
Searching reveals a mix of data. It seems there isn't just 1 yoke for the 9 inch making it impossible to give a standard driveshaft length. Many posts state the 9 inch requires a longer driveshaft than the 8.5 and 12 bolt, so you may end up needing a shaft that is a similar length to the OEM shaft. You will have to measure and see what is right for your combination 😞.
What was stuck that required you to have to cut the original shaft out of your car?