I just thought of an alternate (yet obvious…how did I not suggest this first) solution to the tie-length issue: bowties.
I had never been much of a bow tie-wearer before college, but having to wear a tux occasionally as well as perform in a singing group that wore bow ties, I quickly learned to tie them (it’s pretty easy actually). Maybe buy one to throw into the mix and see how son likes it. And no, pre-tied is not acceptable. 
Definite NO to pre-tied bowties!
I’m a big fan and its mostly what my son wore.
My son has been sent to school with pre-tied bowties as well as some that he have to tie himself. I have a hunch he will use the pre-tied ones most.
@queenmother: I can say that pretty much every time that I’ve been out in black tie in a hand-tied bow tie, I’ve gotten a compliment on my tie/knot. I think it’s a good life skill for guys and I encourage your son to use pre-tied in emergency situations ( as in “OMG, chapel is in 3 minutes and I’m not even dressed”) only.
It’s like learning to tie a shoe for the first time. Once you practice a few times, its easy peasy.
DS will have to have a tie tying session with dh tonight or tomorrow since he will need to tie his own tie at school on Sunday. It all starts at home.
Note on Bow ties: At the Hill, it is tradition that only seniors wear bow ties. YMMV.
@gusmom2000: Do violators get hazed in some way that may or may not be mentionable on the public side of the forum?
Upon further reflection, and based on my own family, (Grandpa, I’m talking to you) you also might want your husband/father/FIL to read as well. 
What about zipper or clip-on ties? I saw Gus Fring using a clip-on tie so it can’t be that bad?
I don’t know about the rest of you, but I refuse to take fashion advice from a meth distributor.
In all seriousness, if a kid can tie a shoe, he can tie a tie. I don’t see clip-ons as being valid past K-2, certainly not in HS. I will also tell you that it is not uncommon for the guys to tie the tie once, and then loosen it and slip it over the head until the next wearing.
^That loosening thing will work for a regular tie but not for a bowtie. 
His Dad has taught him how to tie a bow tie and a regular tie. He has some of each. I just know the laziness will win out. Maybe I will be pleasantly surprised. I imagine that he will wake up every morning rushing to class. He has spent the entire time since acceptance trying to adjust to waking with an alarm clock. It has only awaken him once(the first time he used it). I have no idea how he will wake himself every morning but he will have to figire that out on his own.
I suppose cutting the tie to length is out? Who sees the skinny end anyway?
True, but then I only wear a bowtie with formalwear. Anything else just screams Urkel to me.
There is also the possibility that the kid’s roommate will be so disgusted by watching kid repeatedly tie, untie, tie a too long tie that roommate will take one from his own closet, tie it, and throw it at said kid to wear. But I don’t think that happens too often.
And hazing for bow ties…not as far as you know.
Question for parents of boys. When they are growing rapidly, do you buy everything large and just try to predict how they will grow into it? In other words, how critical is fit? This is in part due to my interest in snagging some post black-friday deals and stashing the shirts away for next year . . (I could figure this all out when he was little and in boys clothes but now he is in men’s clothing).
@sadieshadow Unless it is a super duper good buy, I really never shopped ahead of time. I feel like most retailers have good sales at other times of year now. I’d rather buy to need and fit. Sometimes a growth spurt can mean skipping a size or season limiting the usefulness of something bought with growth in mind.
Answer from a boy: I agree with @doschicos . You can’t predict growth at this stage. And it’s not like there will not be sales between now and next year.
Hmmmm. OK. I will try to be more patient! I think I am also a bit excited about this whole process.