I cannot see how swearing is being labelled as agressive here and shouting is not!
OP the adoption boards on mumsnet are very good and most there will totally know where you are coming from and may have advice.
Just so you know, my advice (if I were in your shoes) is...
Write all your points out in order (either order of importance or potentially chronological if you feel there is a history of this TA behaving badly to your son)
Take your partner/dh (if you are in a couple) or a friend or relative to the meeting if you feel you will need support
If you do that, brief your supporter so they can remind you of items you forget/if you become distressed /or advise them to remain quiet if you would find that better support
Practise what you will say so you do not get upset
When I spoke to the school about my son I did not say 'he has suffered XYZ' I said 'Children who come through the care system have usually suffered/encountered neglect, been seperayed from birth parents and several foster caters etc... If it helps to speak in this way do that
Clearly relate how the incident was related to you
Listen to comments
Make notes
Request an action plan be made there in your presence (politely) even if action plan will be finalised later
Remind them that no 5 minutes of school work time will ever benefit your child enough to make up for this incident which has caused stress to your child and family and led to his exclusion. (Optional!)
Actually it is all optional! But that is what I would do.
When I reminded one teacher that my son had lost his birth family and foster family, she asked me if they had died!
Some teachers will not understand what bring on the the care system (and the reasons for it) does to kids. The PP money could be used for TA education.