There are many car rental companies in Honolulu, Hawaii. But almost all of the companies won't let you use their car for the road test to obtain Hawaii Driver's License.
This info. is mainly for the people from overseas. As long as you have the valid driver's licence from the countries signed the Geneva Conventions, and would like to get a HI Driver's License, you can rent a car from the company I know of.
Will let you know normally within biz 24-36 hrs which website you should go to arrange a car.
They will need to get ready for the document that you will need to present to DMV, so you will need to reserve a car well in advance.