There are two flavors of 529 accounts the prepaid ones and the ones where the amount you invest is totally up to you.
In the prepaid ones you purchase by the year or by the semester. The younger the child the lower the cost. The big risk is that if the child decides to not go to school in that state many of the benefits disappear.
For example this is how the Virginia prepaid plan handles the situation when the student doesn't go to a state run school:
Private Institutions: The contract will pay the lesser of 1) payments
made on the contract plus the actual rate of return earned on the
invested funds, compounded annually or 2) the highest in-state
undergraduate tuition at a Virginia public institutions in the same
semester the benefits are used.
Out-of-State Instituions: The contract will pay the lesser of 1)
payments made on the contract plus interest at a reasonable rate of
return based on institutional money market rates, or 2) the average
in-state undergraduate tuition at Virginia public institutions for the
same academic semester the benefits are used.
Another issue with the prepaid plans is that these only address tuition. The parents still have to be prepared for room, board, books.
But for your situation being reasonably sure you will be moving make the prepaid plans not very attractive.
The choice of 529 plan in the situation where you are very sure you will not be in California for the next few decades does have an interesting wrinkle. Normally you have to invest in the state program where you live in order to get the tax advantage, but California doesn't offer a state tax break on investments.
Some people when they move states they rollover the 529 money into the plan for the new state. Some may do this because they want to only have one plan, though that is just a paperwork issue. When you rollover the funds the first state will generally recapture the tax break they gave you. Some states will treat the rollover as newly invested funds, and give you the tax break on the incoming rollover.
That means that if you start a fund in California, which doesn't give you a tax break, but rollover the funds after you move into a state that does give a tax break; you might still end up with a tax break.
For you: You have to decide if the performance and fees for the California plan make sense. Picking either a plan of another state, or a plan not tied to a particular state may make sense if it can save you money, because you don't have to balance the loss of a state tax break.