I don’t fly for Hawaiian, but you should not have a problem as long as you are boarding early enough for there to be overhead bin space. As with any airline, there will be some individual working somewhere who has a thing against instruments, but as long as you are nice they will usually keep quiet and let it go, especially since that is the policy now.
I rarely see any issues as I fly around, and of course it helps that the Captain that is trying to resolve it is carrying a guitar:)
The last problem I saw, and I felt horrible, the girl had a brand new 200 series guitar in the HSC. The case got damaged, guitar ok, but she was just bringing it home for the 1st time.
So, check your carriers boarding policy and pick a seat so that you can be in an early boarding group, or you may pay for early boarding with some airlines.
Don’t let stressing over your instrument take away from the trip, Tommy Emmanuel has been checking his Maton’s his whole career and never had any problem as of the last time I saw him(2016?).