It isn't true that all cockapoos are easy to train and even tempered. It isn't the best cross and if you get a complex cockapoo, you need to commit to working closely with behaviourist or good trainer over the long term. Even then, you may not help the dog become a calm, reliable companion.
Cocker rage has largely been bred out of cocker spaniels, because good breeders only breed from dogs who have been health checked as well as from breed lines with good temperament.
Cockapoos look like Disney designed them, they're usually very physically attractive little dogs. Sadly, they are all to often bred by money making puppy farms, or hobby home breeders whose only motive is to make £1500-£2500 per puppy. Bitches have two litters a year in dreadful conditions. Little wonder that so many of these dogs have the kind of behavioural problems you describe. 9months is the age many of them manifest.
I don't understand why a behaviourist would recommend re-home for an aggressive dog. No reputable breed specific charity would re-home a cockerpoo who has bitten. Especially one showing the problems you describe OP.
Your husband is being irresponsible. I'd suggest you go to see your vet together, give the vet an honest description of the dogs behaviour and take advice from the vet.
There are so many dogs in the world, I don't wish to sound harsh but, we don't need unstable aggressive dogs.