Lots of factors when it comes to ACL- how much damage ie is there MCL or PCL issues too. You do not know until the cutting starts. Were the tear happen on the ACL, how much longer is the ACL?? What other stuff is floating around- cartilage, nerves, blood vessels, etc etc. If its a clean tear with no other issues, modern time is MUCH less depending on the players healing factor. Its not uncommon to be back in 6 months. Plus it depends on where you play.
Back in the stone age the GOAT Jerry Rice came back in like 4 months when he was 39(?)....before all the advance in surgery which is mainly allowing the swelling to go down and not having as much scar tissue(much less cutting) thus allowing some to come back faster.... They just have a better understanding of the ACL now.