The FAR's would beg to differ. While on mandatory rest you are free from ANY and ALL obligations to the company, to include ANY and ALL telephone or other availability.

So the "mandatory" 9 hours prior check is ILLEGAL. Both scheduling and DALPA will try to talk you into doing this but if you press the issue and point out that it is illegal, they back off. If they don't, call the FAA and tell them you have a mandatory obligation to the company within your 24 hour mandatory 30 in 7 rest period and see how far they want to take it in the name of "productivity".

Now, if they want to force you to schedule check, or even report, immediately at the end of your 24 hour rest, that's fair game and they can do it. BUT, if they do that, then that is considerted a break in rest and will count when you need to look back to find your min 8/9 hours rest for a subsequent duty period. So a 5 AM report or Short Call really becomes a 00:01 duty in because at 5 AM you can't look back and find rest until you get to the actual rest period free from duty, which was the end of your mandatory rest.

The company obviously wants us to obey "past practice" and violate the FAR's on this because it helps them staff less pilots, and DALPA wants us to look the other way because they don't want to spend constructive engagement capital on this, but an FAR is an FAR.

While on mandatory rest, you have NO OBLIBATION whatsoever to the company. Period.

Now, they CAN assign you something that starts one minute (or any time) after your mandatory 24 hour rest, IF, and only if, they notify you of it prior to the start of your mandatory rest. But legally don't have the flexibility to put things on your line while you are on that rest, require you in any way during that rest to check it, and then use the time between the end of your mandatory rest and the start of your assignment as retroactive rest. If there is nothing on your schedule at the start of your mandatory 24 hour FAR rest, then you are off the hook for 24 hours. Then you are either on long call, or if there is something on your line under 8 hours from then, your duty day starts the minute your 24 hour rest period is over, otherwise you are doing an illegal assignment per the FAR's. The only exception to that is if you freely choose to check your schedule and self-notify. But that is 100% your choice and it is a violation of the FAR rest period for the company to, in any way, require you to do this.

Stay legal.