
Certified GKH Gardening Expert
Most fall bulbs can be planted anytime before the ground freezes. In zone 9, you probably don't experience ground freezing. You don't say what kind of bulbs you have but some, like tulips and daffodils, need a chilling period to produce blooms. Even zone 6 is not consistently cold enough for tulips and they are treated as annuals. I would go ahead and plant what you have. December is not too late.
https://www.gardeningknowhow.com/garden-how-to/gardening-by-zone/zone-9-10-11/zone-9-bulbs.htm
https://www.gardeningknowhow.com/ornamental/bulbs/bgen/chilling-flowering-bulbs.htm