Your employer is not "requiring you to attend religious services." Your employer is requiring you to assist the disabled adults in your care while they are engaging in an activity they have chosen.
Your employer could not force you to engage in prayers, take communion, or otherwise participate in religious activities. However, if your job includes assisting your clients in going other places, you can't refuse to take them to church based on your own beliefs.
So the short answer to your REAL question -- not the one phrased in your headline -- is "yes."
Be respectful... just as, it appears, you want religious people to respect your decision not to engage in religious activities.
Please understand that this is a general discussion of legal principles by a California lawyer and does not create an attorney/client relationship. It's impossible to give detailed, accurate advice based on a few sentences on a website (and you shouldn't provide too much specific information about your legal matter on a public forum like this, anyway). You should always seek advice from an attorney licensed in your jurisdiction who can give you an informed opinion after reviewing all of the relevant information.
I agree with the other two responding attorneys. If one of your job duties is to take the individuals you care for to church, then you have to take them to church. It should not matter where they need to go. It is your job to care for them and take them to places as instructed. You are not "attending religious service;" you are simply taking care of the disabled individuals as instructed by your employer.
Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.