Do stop blaming yourself. Babies can be hard to work out and if you are exhausted, it makes everything feel even worse.
I have a 9 month old DS2 (who I don't think is high needs) and I have a DS1 (who definitely WAS high needs). So I've been there too.
I think 9mo is a very "frustrated stage" for lots of babies, when they are just developing real mobility and starting the first sounds that will become speech.
I know my DS2 is now unwilling to be captive in anything (pushchair, car seat, bouncer). He has been crawling for a couple of months - which frustrated him for a while too - and now he can cruise furniture but not walk unaided, which annoys him. So I try to make sure that there are long periods of the day when he can roam free as otherwise he's constantly annoyed. (Sod the housework.)
He is also so excited by his development that he finds it hard to work out when he wants to sleep (and he is brilliant compared to DS1 who didn't really nap at all). So he is often tired and grizzly when he is over-tired, which is most of the time.
And remember too that 9m is prime separation anxiety time, so it's likely that your baby is realising they are not part of you for the first time. I always think that makes babies more hard work for a while because they don't want you to put them down. DS2 is like that and like I said, I don't think he is a hard baby compared to his elder brother, who really wanted to get back inside the womb
.
We co-sleep and I breastfeed too. I'm back at work full time so very tired too. My relationship with DH has definitely had to take a back seat - he feels knackered out too.
I don't know if you want any specific advice or just the chance to vent. But you are not alone and don't beat yourself up. Parenting is hard work.