Yes, TurboTax Online will prepare a California return with itemized deductions. However, the itemized deductions need to be entered in the Federal return first. Then, when you prepare California, the information from the Federal return will flow through to the California return and you will only need to enter adjustments for items that are different for California.
In many cases, under the current law, taxpayers may be able to itemize for California when they didn't have enough to exceed the standard deduction on the Federal return.
California Schedule CA shows the differences between the Federal and California returns. There is not a separate California Schedule A, just differences shown on Schedule CA between Federal and California.