If you are using TT Online, you won't be able to access your forms and worksheets until you pay, and even then, you can't directly edit the forms like you can in the desktop version.
This is what the California instructions say for schedule CA:
Line 9 – Investment Interest Expense
Your California deduction for investment interest expense may be different from your federal deduction. Use form FTB 3526, Investment Interest Expense Deduction, to figure the amount to enter on line 9, column B or column C.
Because you can't access the form, and no one on this board can see your tax file, there's no way to help troubleshoot why you might not have a CA form 3526, or why you might not qualify for the deduction.
You may want to contact Turbotax customer support and ask for a California state specialist to look at your file.
