From JetBlue's site:
Check-in Requirements for International Travel
A valid passport is required for ALL customers (regardless of age) who are traveling to/from the United States and any country in the Western Hemisphere.
Please note: If the name on your travel documents does not match the name on the reservation, you may be required to show additional documents such as a notarized marriage certificate.
All customers must be checked in for their flight at least 60 minutes prior to scheduled departure and must be in the gate area at least 20 minutes prior to scheduled departure.
If you are traveling to an International destination, please check in at the ticket counter. We will not be liable for any charges incurred for baggage that was checked late, nor will we be liable for delivery or compensation for late checked baggage.
Please see specific destination/citizenship information for additional requirements and also if you are traveling with children under the age of 18.
NOTE: Some countries require Proof of Return/Onward travel which will be requested at the departure airport.
Personally, I think a mid-morning departure might be a busy time at the airport, surely you *can* show up at Logan 90 minutes before your flight, but I'd give myself more of a cushion, perhaps 2 hours. You're presumably headed on vacation and it would be a shame to not get on the flight because you showed up too late.
I don't think there will be issues checking-in as from what I remember you can check-in at a kiosk and then you wait in line for the bag-drop (I'm pretty sure this is what I did when I went to Aruba on B6 earlier this year). Security may be a different story though.