Unless you have no choice but to rely on your son to get himself up in the mornings, then I would try not to make too big of an issue of it. My son has always been a very heavy/deep sleeper. He used to occasionally sleepwalk, and sleeptalk as well. Night potty "training" took a long time, b/c he would sleep so deeply he didn't feel the sensations to wake himself up to go to the bathroom.
He is now in 9th grade, so he is 14. He is better about getting up now, but still mornings are very hard for him to come awake. And his teen body clock makes falling asleep at 9:30 p.m. difficult as well. I usually wake him up and stand there until he speaks to me (otherwise, there is no guarantee he even is awake at all), then wake up his sister across the hall, and double back thru his room and speak to him again (until he responds). Sometimes, I have to call for him again.
Unless your son purposefully is defying you at bedtime and not going to bed when he should, or sneaking electronics and playing on them instead of going to sleep, and unless you HAVE to rely on him being able to get up on his own, then I would just accept that he is slow and hard to wake in the morning, due to his internal body clock. And try to figure out a system that works, including asking him what he thinks can be done.
My son takes morning showers now. It helps wake him up and get him moving. One he is out of the shower, he is ready to go in no time flat. He just has to get AWAKE first.