You are at the HARDEST point of an ADHD person's life; Puberty.
During puberty ALL the coping mechanisms that we learned during childhood just FLY out the window, and we have to start all over again.
Know... when he's standing in the bathroom staring... HE IS being hyperactive, his mind is going a mile a minute. (There's a quote: I may not look it, but at the cellular level, I'm really quite busy...it's also why they changed the name in the new DSM, all forms of ADD/ADHD now have the H attached, because you're either hyperactive mentally, physically, or both). Imagine the BEST book you've ever read, or the most amazing movie... THAT'S what it's like going on in his mind. Well, mornings can honestly be 'flatline', but the REST of the time, that's what is going on. Times 5.
The homework thing isn't going to get better for YEARS. If he's in gifted classes, it will get better sooner (gifted and AP classes actually start handing out semester long syllabi with every assignment on it a LOT sooner -aka before college- than regular classes, have less HW to begin with, and it's more interesting), but it's still going to take several years.
Stimulants help (caffeine is really a gift from the gods, esp if you aren't using meds), blasting music helps (yes, I know it LOOKS like it would be distracting, but our brains work differently), rewards help (punishments DON'T... with neurotypical kids punishments for failing to regularly complete or turn in HW help, for ADHD kids, it makes it far far far worse).
Tons and tons and tons of things HELP, but it really is going to take a few years.
Largely, because he's having to *start all over* to relearn coping mechanisms. When he's done with puberty he'll be at the independence level that neurotypical kids are at 9 or 10. ((AKA different expectations on your part will make life a LOT easier for both of you)). It's harder in many ways with ADHD kids, because most ARE gifted. It's doubly frustrating for parents who look and see "How can you be reading Julius Caesar, but your 5yo brother can do things you can't?!?!"
Read "You Mean I'm Not Lazy, Stupid, or Crazy?!?" by Kate Kelly & Peggy Ramundo http://www.amazon.com/You-Mean-Lazy-Stupid-Crazy/dp/07432... (It's nominally for adults with ADHD, but it is the BEST book for parents, because it raelly gives a 'whole life' look at their kids and what the results or consequences are with ways of doing things, as well as dozens of stories and coping mechanisms and strategies. Go start pouring through www.additudemag.com (best online resource for ADHD that I've ever found... most resources are about ID'ing adhd, additudemag is about LIVING with it, and living well.
BIGGEST TRICK for doing the same things every day? NOT thinking about it. Don't make him. IT WON'T HAPPEN. If he has to stop and think about it, it will get lost in a ball pit of FAR more interesting things, and he'll just stand there. ROUTINES. Getting the same things ground in time after time after time... so your mind can be thinking about birds, and shakespeare, and DNA, and your left foot, and a conversation you had last month, and what the natural result would be if gravity only worked in 15 minute increments (yes, all at the same time, not 1 after the other). When you've got the routine down, you'll still be thinking about the interesting stuff, but your hands and body will be turning on the water, showering, brushing your teeth, putting gel in, dropping your towel on the floor (I know, rolls eyes), getting dressed, and you find yourself completely ready to go, all without thinking about it.
((My 9yo doesn't have a 'chore chart' per se, he has a LIFE chart. Mornings literally look like pee, flush, start the shower, use my puffer, brush my teeth, take a shower WITH soap, get dressed, get breakfast, wash my breakfast dishes, find my backpack, make sure I have what I need in my backpack, play. That's the morning section. He doesn't go item by item checking them off, he looks at it at the end to see if he missed any, and THEN checks each one off... or goes racing to fix what he forgot. Then there's school, play, homework, help with dinner (mornings need to be REALLY outlined, because we're still half asleep, later in the day, less)... but the BALANCING items ; like playtime are on there as well. He didn't need this chart until he hit puberty. Because I got him into a routine as a toddler, naturally helping with everything. But as soon as hormones STARTED at age eight, he started getting distracted. Fully into the hormonal shift at age 9, that chart isn't just helpful, it is absolutely necessary. He's relearning how to do all the things he used to be able to without thinking about them.))
As far as independent, much less 'success'? Oh honey, yes. ABSOLUTELY. YES!!!
ADHD (in all 3 forms) runs, skips, hops, and sliiiiiiiiides through my family. It's pretty easy to spot, we're the ones who do things just a little differently than the rest. The astrophysicist who is also and outdoor adventure gear inventor, the military folk (you find a LOT of adhd people in the military), the artists (writers, muscians, photographers), the list goes on. Most combo. Like my mum who was both a professional artist and microbiologist and stay at home mom/traveller. Myself I'm ADHD-c. I joined the military straight out of highschool, and am now quad majoring in school (anthropology, nursing, fine art, and psych). The last one is an accidental degree (psych classes are easy, so I padded every quarter with a psych class for the easy A and the financial aid bump, I in no way want to work in psych, they're just fun and interesting classes that would bump me into 12 credits per quarter aka full financial aid instead of 3/4s financial aid). The rest is super typical ADHD combo stuff. It looks like a BIZARE combo, until you realize that I want to do double duty as both staff archaeologist and staff nurse and the art is to keep me sane. I also write, teach, do a lot of sports, blah, blah, blah. SUPER typical ADHD 'all over the map' stuff. Since I'm ADHD-c my interests tend to split mental and physical, but even for the pureists (mental OR physical, but not both), interests tend to get reeeeally varied.
We take longer. We do things in more depth and detail. Our emotions are more intense. We open mouth and insert foot on a regular basis. We drive our parents nuts. We have to find work arounds (like hiring an accountant to pay our bills on time, and having a maid to keep our houses presentable, and working jobs that aren't 'punch in and punch out')..
But we do 'get there'. I promise.