Then you are pretty much my zone. It is not too late to plant and you will have a long growing season, nearly all year. You can plant nearly every month of the year except in the peak of summer late June- August. But face it, who wants to be out in the garden at that time of the year anyway, hit the beach instead.
Actually, I do start some of the "winter" vegetables in July. Brussels Sprouts and broccoli take a while to mature and need to mature during the cool months, so I actually start them in Late July.
Some things you have to do "on time"
1. If you have roses, you will have blooms at Christmas, but at some time you have to decide to cut them back sometime.
2. If you want to give the garden a "rest", there is no winter to put the garden to bed. If you want to revitalize the soil with a cover crop or solarize for other issues like nematodes or weeds, you have to do it sometime. Usually the best months to do that is July and August anyway, you will get the best results from solarization. Cover crops take about 6 weeks to mature and till in at flowering. I usually do that Jan-February.
3. If you want to plant bulbing onions or garlic. You need to get the southern varieties and plant them late September-November. Chill the garlic for 6 weeks to winterize them. I plant onions from seed and I use Texas Granex. They will take about 5 months to mature.
4. Most of the cool season plants won't do well in summer unless you plant them in morning sun, water them more and/or provide some shade. In the cooler months I plant heat resistant lettuce in the sun and in the summer I plant them under my citrus trees. Red lettuce does better in the heat. Romaine best only in the cooler months.
5. Use heat resistant varieties and consider tropical and Asian plants. They do better in the heat. Mexican mint marigold is a good tarragon substitute, since French tarragon cannot handle the heat, NZ hot weather spinach is perennial and usually, it is like sweet potatoes, if you let it sprawl it just goes everywhere. I would use it like an edible ground cover. Asian greens, snow peas and chayote are good in the cooler months of the year and beans, tomatoes, eggplant, and squash do better in summer.
Some things you have to do all of the time
1 Weeds, disease, and bugs are 24/7 , 365 days of the year. You have to stay ahead of them. Work in the early morning and after 3 p.m. to stay out of the heat of the day. There is no winter to slow or kill any of these things.
2. It is good to start small, a 3x6 plot or even a 4x25 ft plot would take less than one hour a week to keep up with, especially if you automate the watering and mulch to control the weeds.
3. Plant for succession. SFG is a good way to start since you would be working with one square at a time. A SFG bed is typically 4x4. Your 3x6 plot is a little bigger, but can still work out in a SFG plan. Site your garden in full sun and put a trellis on the north end of the plot. Make sure there is access on all sides. Do not put the bed up against a fence, it makes it harder to get around to the back side, although you should be able to reach across 3 ft., but the fence can casts shadows on the bed for part of the day, plants tend to lean away from the fence, and if it is a solid fence or wall, it can block air circulation which can promote disease.
Happy gardening in Hawaii. Gardens are where people grow.