[date] JIRA JQL searching by date - is there a way of getting Today() (Date) instead of Now() (DateTime)

In case you want to search for all the issues updated after 9am previous day until today at 9AM, please try: updated >= startOfDay(-15h) and updated <= startOfDay(9h). (explanation: 9AM - 24h/day = -15h)

You can also use updated >= startOfDay(-900m) . where 900m = 15h*60m

Reference: https://confluence.atlassian.com/display/JIRA/Advanced+Searching