I agree. 2 different and distinct questions/issues.
Alarm clocks in their rooms? Daughter has one but doesn't use it. Son has had one at various times, but doesn't use it, normally.
Son is older, and has historically been a very, very deep sleeper. The kind that you had to physically shake him to wake him up, and then go back 2 or 3 more times b/c he has no recollection of the first 2... before he is actually consciously awake. Now that he has passed through puberty, this issue seems to have faded. Unless he is over tired, he wakes up fairly easily when I open his door and start to walk into his room. Before, I probably could have exploded a bomb in there and he wouldn't have known. Now, he hear's my footsteps half the time (almost like "mom ears", lol).
So, he was not *allowed* to use an alarm clock for years, b/c he wouldn't hear it, but the rest of the house would. And we'd have to go shut it off, or wake him up to shut it off, etc, and my husband works shift work and this just doesn't work when his schedule dictates that he still be sleeping when son is getting up.
Because of this issue, I have always gone to wake him up. Since he is directly across the hallway from his sister, I wake her up, too... so she doesn't bother with an alarm clock, either, unless she wants to get up early on a Saturday or something for some special reason that doesn't involve me. LOL
As for the ADHD/ODD issues... those are separate from using an alarm clock, in my opinion. I hope the other commenters can offer helpful information regarding being organized and getting out the door. My kids are fairly typical in this regard and have both gone through phases where they were easily distracted from what needed doing (or just slow, ranging from not eating b/c they hadn't been awake long enough to just being young and distracted by some toy in their room) and phases where they were ready to go and sitting and waiting on me.
Once my kids hit about middle school age, (11 years old) they seemed to have developed a morning routine that worked for them in getting everything done on time. Since I wake them up, I have just adjusted their wake time to match how much time they need. Most mornings they need about 35 minutes to be ready to go. Son is 16, and this includes his shower time. They both tend to want to skip eating anything.. it seems it's too early for them to want to eat, so they take something for the bus ride or for when they get to school. (Our bus picks up by 6:50 a.m. and classes do not start until 8:00 a.m.)