I would like to plant a climbing hydrangea-but wonder what my chance of success might be..

I live in Zone 9, Central California-it gets hot here 100+ all summer but little to no humidity. I have a sheltered garden, a Chinese tallow tree and neighbors pine trees shade it. (Canary Island Pines-needles constantly on the hill like mulch) I trucked in dirt so its a hill. There are other hydrangeas growing there (daughter worked at a grocery store and kept bringing home the half dead ones), ferns, campanala, violets and lenten roses.

I would like to grow the hydrangea up the tallow tree.

I dont know which one to buy? Some of the CH say only to zone 7, there is one, Moonlight, that states to zone 9.

I know these are pricey and its a long time to invest,,so I want to get the right plant.

Thank you for your advice and help.