I fly the Curacao- Bonaire route at least once a week with Insel. The MD-8x does have overhead bins, as is shown in the picture in this thread. The Embraer does not, but that is not a problem. You just take your carry-on with you and at the bottom of the airplane stairs, you hand it to the lugguage guys. They then put it in the cargo part, which is very small, they cannot throw the lugguage around or it will go through the walls
. They are normally quite careful with the bags, since a lot of business guys with laptops fly this route daily, so they know to handle carry-ons with care. If you are worried, just tell them to handle it with care and they will.
Once the plane has landed, just disembark and wait for the guys to get the carry-ons out of the hold, they will hand it back to you directly of place it on the tarmac.
I find Insel to be a nice airline. Yes, they are frequently delayed (at one time 6 hours for a 20 minute flight!) but I got my bags every single time, so for me they are ok. The others here are not much better. DAE is about the same, Divi Divi is the best but their planes are so small that bringing dive gear is not an option.