Originally Posted by CPH-Flyer

ANA is generally very good at checking luggage across separate tickets. So there is no need to actually do anything. Do bring a print of both of your e-tickets as that will make life easier for the agent.

Seperare bookings can't be linked that way, but if you call ANA they can make a note in the booking, it will still require some manual intervention from the check-in staff though.

Staying in Haneda 8-9 hours is not a problem, even overnight is not a problem. The airside transit hotel is still closed, so the time have to spent in the lounge or somewhere in the terminal though. Narita is the one where overnight transits are impossible.