The first thing you could do is make the cat an indoor cat and provide a litter box.
Most cat owners do let their cat out but don't provide a place for them to do their business outside. It is not done on purpose but unlike dogs, people usually don't have to go around and pick up after their cats. Cats bury the evidence usually in soft bare ground or a child's sandbox and they prefer not to mess up their own place. That usually makes other people mad.
You can use outdoor repellents like outdoor no or critter ridder to keep cats and dogs away from certain areas. Cats also do not like citrus peels. The only down side is that the peels dry up to you have to keep putting out more. You can plant coleus canina in the flower bed to keep the cat away. It will only protect the area you can smell it. I think it stinks.
I try to work and plant my garden the same day to prevent finding stuff in my garden from the stray cats that come by. My cats are indoors. If I can't do it in one day, I wear gloves and I use the orange temporary construction fencing to cover the garden.
In your flower beds you can use physical detterents like
burrying chicken wire just under the surface of the soil so the cats can't dig in it.
citrus peels and citrus oils
mulch with pine cones or gravel, they don't like how it feels
Use a motion activated sprinkler
https://www.amazon.com/Hoont-Powerful-O ... M64HPQARHX
You can use cat scat mats to cover bare areas.
https://www.gardeners.com/buy/scat-mat-c ... 92448.html
If you are going to let the cat outside, you need to provide a place for them to do their business. They like privacy so not an open space with a lot of traffic. Actually a child's sandbox filled with cat litter and sand would be perfect. You still have to clean out the sandbox and replace the litter. And keep the kids out of it. If you have a kid and a sandbox, keep the sandbox lid closed when they are not using it. Cats are clean animals and they won't use any litter box if it is dirty or if another cat has used it. Separate boxes for multiple cats. Keep other animals away from it. Dogs like to eat cat poop. You can use a doggie dooley for cat poop.
Give the cats a nice place to hang out. They like a tall perch with some shade. Plant mint in a large planter in partial shade like under a small tree or shrub or in a gallon can. A cat will sit in it every day until it dies. I planted catnip in a box but put a wire cage over it so the cat sat on the cage and not on the catnip. Cat tree for climbing and some shade in a deep box or tube so they can feel safe and also ambush you. My cat used to like to sqeeze into a 12 pack soda case and ambush me when I passed by. Wrap sisal rope around a post and give the cat a cardboard box to scratch. Cats have to keep their claws sharp, so it is better to provide them with a suitable scratching post otherwise it will be the furniture. Do not give them carpeted cat scratchers. You will just be teaching them to scratch carpets. They also like to scratch tree trunks, but most trees can take it. Cats eat grass, and some of them like cat grass. You can grow a patch for them.
My cats pee several times a day but usually poop right after they eat in the morning. It is better to clean up right after that. Litter boxes should be cleaned daily.
P.S. I tried the automatic cat box.
You still have to empty it and my cat did not like the sound of the motor. It also took 8 D cell batteries a week to keep it going.
The one thing every cat person knows and that is that dogs have owners and cats have people
Every cat person knows the cat trains them to do their bidding.
Cats have routines, it makes it easier to find them since they will be at certain places at certain times of the day
The highest perch or table will be claimed by the cat, get used to it
Cats know their name but will never come if you call them and they don't want to come.
Cats love cardboard boxes. Who needs fancy toys.
Multiple litter boxes and scratching posts are a necessity. The cat will tell you if they like the litter box. If they don't use it within 5 minutes they don't like where you put it. Find another place. P.S. My cats have their own closet.
I have had cats a long time so I have a couple of area rugs but mostly tile and laminate floors. It is hard to get cat fur out of carpets and I do not have carpeted scratching posts. It is easier to clean solid floors.
It took me six months to find a replacement for the living room fabric couch. I now have a outdoor bench and outdoor seat cushions for my living room. As it turns out the cats don't like to scratch the material that the cushions are made of. My latest cat though likes to scratch rattan furniture. I may have to replace those as well.
A bird feeder outside a window is great entertainment for an indoor cat, and it keeps them out of trouble.
Not all cats are natural mousers. Hunting skills are something they have to learn.
3 a.m. is broad daylight to a cat. If you are up at that time, they will expect you to play.
You won't need an alarm clock, the cat will make sure you get up.
Happy gardening in Hawaii. Gardens are where people grow.