if you just put him in your vehical and no one can see in basically then there is no need for a health certificate but it wouldnt be bad to get one just in case. But if you are going to use like a horse trailer or a stock trailer then you need to get a health certificate because if you are stopped you have to have those papers. And you are more likely to be stopped or need to stop and report what you are bringing into the state if you have a trailer of any kind. I know Florida is real stickler about this and Texas maybe as well but I dont know how other states are. NJ and its bordering states dont care one bit.
I pass CA all the time. all the same stuff Stacey said - if you are moving him with a trailer you need a health certificate. If you have him in a crate in your car and he isn't easy to see you'll be fine. I cross the check points with goats all the time and don't have issues.
i've passed with goats at the AZ/CA border in blythe dozens of times with all kinds of animals and never had an issue. But if you plan on having the goat reside in AZ / or show.. you HAVE to have a health cert thats 30 days recent to entry. had to do it with boers