Fed = yes/no

CA =  maybe/maybe

Fed:  As long as the 100/110% has been paid thru-out the year as required via timely estimates and/or withholding.  You can't just make an estimated payment now/Jan 15, 2021 and have the penalties eliminated.

CA:  Depends on the total income. California has this different rule IF the income for the year is over a million (that amount may have increased...check Form 5805); the 100/110% rule can't be used.   And if the income is less than that, you still have to have paid in the 2020 amounts timely (estimates or withholding) just like the Federal

And paying the CA hit before the end of the year involves evaluating your client's specific situation after considering SALT limitations.  And you should be aware of talk that SALT limits *MIGHT* be suspended for 2021.

Lot of moving parts to your OP.