Google Sheets Format based on time of day and 2nd condition

I have a sign-in sheet where attendees sign-in for their cases. I want to write conditional formatting for the cell to tu red if they have not signed in by 8:45am on the current date - so two conditions - the time is past 8:45 and cell is null (columns G & I in this example: https://docs.google.com/spreadsheets/d/1OzEDH_3ExlcoYBOaxz38mhxlgKOQ7e8Erl9E25yHRko/edit#gid=616211987

Thanks!