I want to make 9AM HST phone appointment to complete my 2020 taxes.

No one in the user forum knows your phone call arrangements.   We do not schedule calls and are not involved in the calls with "Live" experts or with customer support.

You can arrange for the Live help you are paying the extra fee for with your questions from 5 a.m. to 5 p.m. Pacific time.

Phone support is not provided with the Free Edition.  If you are using a paid version of the software or if you purchased PLUS you can get phone support when customer support is there.  Otherwise, post your question here and someone will try to help.

To call TurboTax customer support

https://ttlc.intuit.com/questions/1899263-what-is-the-turbotax-phone-number

Customer support is available from 5 a.m. to 5 p.m. Pacific time Monday-Friday.