Not sure I should be offering advice as my dd can be very volatile .. and part of that is a reaction to stress I think (I'm a worry-wart so not a good role model in that regard)
But, fwiw, how about sitting him down at a time when you are both calm and you don't have visitors and asking him (a) what does he think would help him to get his homework done on time? and (b) how can he help himself to manage his own stress levels?
eg in answer to (a) possible answers could be: no tv, a little bit every day,snack before starting work, discussing different options with teacher etc etc and (b) punch a pillow, run around the garden, go to bed earlier etc etc
(This is a technique gleaned from one of the trillions of parenting bks I have read btw in search of solutions myself - not original idea by any means.)
You then write down his suggestions very seriously - you can add suggestions to the list too - no discussion or interruptions on either side allowed at this point. When list is you then assess the different ideas together (you gently rule out more far-fetched ones such as lunar rocket beaming me away on homework nights) and you should be left with some workable solutions which you then write out and formally agree to follow.
The idea behind the technique is that it puts the child more in control of themselves and the situatiosn they find themselves in (a stress reliever in itself) and they are more likely to follow the new 'rules' if they have had a hand in making them.
HTH. I've tried it with dd several times and it does take effort to follow through consistently but it has (nearly!) always improved the situation to some extent (in one instance hugely so).
Good luck with it!