No you can not just willy nilly change your children's names on the birth certificates either by contacting vital records or going to the courts. If you want to change their birth certificates, your husband will have to ADOPT them. If you just want to change their last name on other official documents going forward, you can submit a minor name change, though you have to show it's somehow in the best interest of the child to go that way: https://www.nwls.org/Name_ChangeMinors.htm

