Does anyone in the Wailuku,Hawaii area on island of Maui have any suggestions for affordable in home care for my Grandma?

I think this is a question you might want to ask the Hospice Social Worker.
Since she is on Hospice the Social Worker might have some information that could help.
And depending on the help needed and how often Hospice does have Volunteers that can do some things, light housework, shopping, visiting and the like. They can not do "hands on care" though.

There's always Medicaid if she is low income. If not, the cost comes out of her pocket. You can hire privately, which would be cheaper but u should be taking out payroll taxes. IRS does not consider aides self-employed. Agencies charge more but are in charge of payroll taxes.

You could pay under the table. But if Grandma ever needs Medicaid for Long-term care, they may question the payments so you need back up with everything done right.

You should have an Office of Aging. Call them and they can help you.

I think that with a low income, the cost of in home care is almost impossible. Hiring from an agency will be more costly than hiring outside an agency, but then you do not have the insurance, the vetting and etc that agencies provide. Almost all agencies require minimal hours of work, for instance four hours three times a week minimums. And here on the mainland we are looking last I had a friend needing care very recently, at 40.00 hour agency, and she hired someone 20.00 an hour in home.
We are not a hiring agency and I am not certain how likely another Forum member is from Maui, but you may accidently run into someone from Forum who lives there and is taking care of an elder who would have some info re their own experiences. You may also try to access any counsel on aging or elder care outreach.
I sure wish you luck as it's almost impossible trying to find out anything long distance and on the phone these days.