I have had physical custody of my. Child for 9 yr and I let her father take her for Xmas last year. He kept her

If you have an order for child custody and visitation, and your are the primary custodial parent of her, you can contact the local police to enforce that order and get her back. Your biggest problem is going to be the amount of time you let your daughter stay with your ex.  He could try to commence proceedings in Missouri under the UCCJEA and even come to California to assert that the status quo has changed and he should now get custody of her and be allowed to keep her in Missouri.  You should meet with an attorney as soon as possible to discuss your options.  Time is your enemy here!