Awaiting sons diagnosis

Hiya everyone. I'm new here and was looking for some advice from anyway who was in a similar situation or who would have any advice!

We have a 7 year old son who shows a number of traits of Autism/ADHD - he has speech delay, he has high anxiety at school, we have had school reports of him not joining in any class discussions, he struggles to concentrate, he has separation anxiety (he still sleeps with us) and he also has toileting issues. He recently has started to display OCD traits, he has to run along walls a set number of times if someone gets there before he does, he has to perform tricks on our trampoline a set number of times until he is satisfied we have watched him correctly etc. He also gets violent with his siblings when he has his 'meltdowns'. We are waiting on the ASD panel now however we have been told this maybe 18 months to 2 years and we are awaiting appointments for CAHMS referrals but until then we are unsure how to manage this behaviour (telling him off/shouting only exaggerates the problems) and to be honest, the stares when we are out and about and not knowing how to calm him down absolutely break my heart. Any advice would be kindly received. Thank you!