2005 mini Cooper won't crank. Tries but nothing. No warning

My 2005 mini has no dash warning lights on and
doesn't want to start. Seems like she wasn't getting
gas but all fuses were checked the fuel pump was
checked couldn't find issue with those now she's
throwing a code something about it could be a
loose gas cap or faulty gas leaking somewhere but
all those were checked and it's also registering that
the computer is only receiving 9 volts when it
should be higher but again there's no warning
lights on the dash no emails no check engine no
nothing I stopped I got gas went to crank her back
up she would not move and press on the gas the
first few times and she would die out so now she
won't turn over at all