@Letshopeitworks I've worked in several SEN schools/environments over the last few years with children from the ages of 3-15. Some of the children with ASD I've worked with can be very violent, so I know how challenging it can be
I'm a long-time lurker but have made an account so I can comment - hopefully a couple of these things will be helpful to you in the short-term while you're waiting for support.
Routine is absolutely key when working with children who have ASD. In several of the ASD classes I've worked in (including reception) we have visual timetables (with symbols) so they can see the structure of the day. If you google "visual timetables" you can see different examples of them - Twinkl has some generic ones that you might be able to adapt to suit, or software like Boardmaker Studio can enable you to make your own relevant to you. We also use "Now/Next" or "First/Then" cards with the same symbols on the visual timetable to help in transition between activities (e.g. "first dinner, then play") and to reinforce behavioural expectations. If the child begins to resist we use minimal language and say "no, first then _" and keep reiterating it until they follow the instruction (and we give lots of praise when they do)
I know a lot of non-verbal children who become violent because they have no other way of communicating what they want or what's upsetting them. Introducing communication boards with relevant symbols to him and his preferences/needs might help. If you model "I want " with symbols like eat/sleep/play/drink/toilet (or specific ones e.g. raisins if they're his favourite) while giving him the option to choose might help develop his voice and his ability to communicate without violence. As he gets older he would move onto more advanced communication boards (e.g. "I'm feeling " or using symbols with abstract concepts like "help"/"more") but start with the concrete/physical. Twinkl or Boardmaker would again enable you to make them, but google "SEN communication boards" for ideas. Speech & Language would be able to help you with these too.
When you said he's trashing the house, is he picking things up to drop/throw them? That combined with the spinning would suggest he's quite physically sensory-seeking. I've used feathers, glitter, sand, cereal and rice to occupy ASD children or calm/distract them when they're upset (they would rub them through their fingers/ hands, watch them fall, then pick them up to repeat). Ribbons, shaving foam, ice-cubes, bubbles, water play (with cups to pour with), playdough, cornflour slime or giving them paper/material to shred or tear can also hook them and distract them from more destructive activities. I've also known a child who would spin but be calm when listening to music, or would spin with ribbons to watch them move. It would be worth trying sensory bottles or trays if you haven't already - if you google the terms and look on Pinterest, there's lots of ideas. Try him with different things and see if any catch his sustained attention/interest.
I hope some of these strategies help in the short term while you're seeking support, and I really hope the HV can help on Monday too. Please feel free to PM me if I can help further. I really hope things improve soon and you all get the support you need 