Quick answer: generally no in informal probate, unless the will itself requires court confirmation or the estate is formal, supervised, or contested. Run your own numbers in the Hawaii probate real estate sale calculator.
A power that comes with a fiduciary standard attached
The will can require confirmation
The opening words of the statute carry the limits: the powers apply "except as restricted or otherwise provided by the will or by an order in a formal proceeding." A will can require court confirmation, and a judge in a contested estate can order one.
The attorney and title company sort this out first
The estate's attorney and the title company settle whether the will restricts the sale before a contract is signed, by reading the will and the letters together — it changes the paperwork, not the price.
Formal or supervised probate flips the default
In formal or supervised probate, the court must approve the sale, unlike the more hands-off default in ordinary informal probate — a genuinely different process depending on which track the estate is on.
A local probate attorney can review your estate — many offer a free consultation.
Each of Hawaii's judicial circuits handles this the same way, but HRS §560:3-711 applies identically statewide.