For store meltdowns, caregiver peace of mind is also an issue. Consider having cards available to hand to nearby adults for the most difficult meltdowns. Maybe saying some thing like "my child is on the autistic spectrum, and I'm here helping to develop his/her life skills. Thanks for your understanding".

You can't not go to the grocery store :) For your next trip, plan for it to be several long hours. When you get into the store and he starts to tantrum - outside everyone goes to the car. Once he is calm (bring a weighted lap pad and some sensory fiddles to keep in the car - but no reward toys or anything like that). When he is calm, back in you go, if he tantrums again, outside everyone goes. This will likely be repeated many many times at first. Once he goes in and does not tantrum and allows you to finish completely, then provide him a reward (whether it was something he was allowed to pick out in the store, or even a pre-planned surprise you have with you).

You must be firm, and even though you will want to rip every hair out of your own head, if you don't appear to get flustered, it will help him to calm faster. At least that is how it is with my son.

Bring a book for yourself - you will be spending some quality time in the car :)

Hope this helps!

Cheryl: my son's neurologist told me to give it to him. I didn't want to give him anything until a Dr told me too. Your body makes that naturally anyways, just in some cases like children with autism their body's don't produce enough of it.

My 4 year has bad meltdowns in stores also. He takes melatonin to sleep. That only helps with nighttime issues. I have found that the earlier I go to the store is better on him. Or right after a nap. Some days he just won't let me go at all. I know all to well how frustrating and draining it is. If you have someone that could watch him on the days that you know he won't behave while you go to the store. Then let them watch him. I had to do that yesterday. Best of luck!

10 to 9 isn't bad amount of sleep, not great. Darken the room will help, along with same routine (for bedtime and wake time), silent house if you can while he falls asleep.
As far as the store. Go slow. USe a schedule and a list of what you will get. First start by getting just one thing you need and a small treat. then SLOWLY increase the amount of real things to get and a small treat...then once the meltdown routine/habit has stopped. Go back to one thing but no treat, explain beforehand and "make a deal" if you are good (go into detail what this means) while I pick up ___ then you can (watch a video, play on the computer, play outside, ect) when we get home. repeat and SLOWLY increase the amount of real shopping you do, making if you are consistent it will work. IF you have in home behavioral therapist they can help you with the process. good luck!