My 7 has a non axial brise starter fitted, so probably not exactly the same but similar.
When I first had the car it would require a little throttle at start up or would do as yours and just die straight away.
After a very wet trip to Europe the starter would barely turn the car over. So it all got stripped out and the electrics checked.
I found a very rough connection had been added to the end of the main starter feed wire to extend the cable, this had burnt the cable a bit due to it being loose.
Having done a better job and made it all good the car now starts without throttle, even after standing for weeks with the isolator removed.
I guess I am saying, check all the connections on the starter as that is all that has changed, and look for any 'additions' that may have been made.
As has been said the 9.9 V is too low for the ECU to work, mine had similar values but is now fine.
Doug