I think the law is that alcohol cannot be served, consumed after 10pm and all glasses must be off the table. Last call would generally be about 9pm and glasses would be cleared at 9:30 even if you're still drinking.
In "town" some restaurants close as early as 7pm. I live in Kaimuki, a 5-10 minute drive from Waikiki and most of the restaurants in my neighborhood close by 8pm. Zippy's, a local chain that is known for late-night-eats, closes at 10pm. Many mall eateries are also keeping abbreviated hours and closing around 7pm.
A lot of Waikiki restaurants are still closed. Most of the International Marketplace restaurants, many hotel restaurants, most of the small shops serving Japanese tourists, and even PF Chang's have yet to reopen.