One of my teens is like this too. Everyone else in the house is woken up by his alarms (yes, plural, all going off simultaneously), yet he can sleep on through, despite them being right next to his ears. Oh yes, I've got one of these too! Everyone else wakes up, DC is still snoring... I have no idea how it's not waking them up when the rest of us hear it so clearly!
On a more serious note, whichever poster said GCSE prep often starts in Year 9 now is right, but not all schools do the same board, so there are variations between them. (Even though the new 9-1 syllabuses were meant to present subject skills more consistently, regardless of exam boards, the reality is there are huge differences between them, and that can throw even the most organised and enthusiastic student if they have to move schools mid-GCSE studies. (I'm part-time and have taught two of the exam boards in a core subject, and there are very noticeable differences between them).
But if your daughter really wants to stay at her old school she now needs to work with you to prove she can make it work consistently. Might be worth talking to the school so that you all agree on consistent consequences in both places (many schools offer a 'home/school contract' type arrangement the student has to sign) and then a strict time limit - say May half term - beyond which (if your daughter is still late consistently) the only option is move her closer to you ready for September at the start of Year 10. And then stick to it, no matter what.
Heck, I had to get the bus at 7.15am every day when I started secondary school at 11. I had no say in the school, my parents simply chose the nearest Catholic one. But it it was a 12 mile bus ride away. The school subsidised a private coach company to pick us up - there were no public bus services - and because of the meandering route (we were the first pick-up) it took an hour to get tos school. My dad dropped me off at the bus stop before 7.10am every day on his way to work, mum also had work, and that was that. There was no other option, no one to take me, no other public bus service option. School were also hardline on lateness. I wouldn't have dared mess around in the morning to be late for the bus!
Your DD is 14, older than I was, and it's her choice of school! Two advantages I didn't have! So, either she can choose to get her act together (with your help to start with) or she can choose not to = but if she chooses not to, then you have to have the next step/the neq school ready before she gets to Year 10.
Sorry, that was longer than I intended - well done if you bothered to read it all! 