You need to arrive at airport at 8:00am for 9:30am flight as long as you print out your boarding pass head of time. You didn't indicate which airline as some security lines will be shorter vs. others based on the number of flights they have outbound at that time of day.

I think all concerns about subway and luggage are silly as we are talking the beginning of rush hour! The train will be crowded so anyone claiming your neighborhood or subway is unsafe - I would strongly challenge whether that person has actually rode the subway at that time of day? The worse you will see is a homeless person sleeping on the train if it is cold outside or raining/snowing.

Next, I'd suggest you simply ride the A train directly to Howard Beach/JFK station and board AirTran (avoid transfer). Based on the current schedule you would board a 6:59 at 125th st and arrive at JFK at 7:55 and allow another 15 minutes to your terminal (8:10). Allow 45 minutes for security (8:55) [no luggage right] and you still have time to walk to gate while they board your row. I hate waiting at airport so change times to whatever makes you most comfortable. If on AA I'd pad more time vs. if it were United or JetBlue.

You can walk to Cathedral Pkwy and go uptown for 2 stops and switch over to the downtown express train. If a downtrain arrives first board it and switch as Columbus Circle 59th St.

BTW - The A train southbound will be filled with other travelers and airport workers so even if you are uncomfortable with a new route just look for another person with luggage.

I strongly oppose the idea of going to 34th St to jump on LIRR via cab as you are simply wasting time and money for the same end result. No cab will beat the speed of the train in Manhattan you live in NYC with the advantage of public transportation so use it. You have nothing to worry about!