Omicho Market is well worth adding to your Kanazawa itinerary. The first floor is the liveliest part of the market, with fresh fish, fruits and vegetables, prepared foods, and various local Kanazawa products all concentrated there. The Omicho Ichibakan building also has a basement level and a second-floor dining area where you can buy daily necessities, eat, or take a short break.
If your main goal is to explore the market, I recommend coming in the morning. Although this isn't a traditional morning market that only operates early in the day, many fresh fish shops start packing up in the afternoon, so there will be far fewer options if you arrive too late. Some shops also have shorter hours on Sundays and national holidays, so if you want to see the entire market, it's best not to come too late.
The first floor isn't just seafood; there are also many fruit shops. It's great for travelers who can't conveniently buy a whole box of fruit, since you can choose a portion to eat on the spot. The seafood shops still retain much of the feel of a traditional market. Most products are intended to be taken home and cooked, but some large fish shops also offer freshly grilled seafood that you can eat in the seating areas they provide.
If you're traveling with seniors, children, or a larger group, I would recommend going straight to the second floor to find a restaurant. Seating at some of the popular seafood rice bowl places on the first floor can be cramped, while restaurants in the second-floor dining area usually have more space and make it easier to find seating for groups. They also offer a wider variety of dishes. For example, the restaurant where I ate on the second floor had a kids' meal, making it a more child-friendly option.
Overall, Omicho Market clearly retains the feeling of being “Kanazawa's kitchen.” Although it's also a famous local tourist destination, it still feels very local and not overly touristy. The fruit and vegetable shops, fresh fish shops, food shops, household goods, and other non-seafood products actually give the first-floor market even more character.