You would have to walk through a lot of industrial areas to get to work, so that's not really an option.
For the 7, you would be traveling against the flow of rush hour traffic, so the crowds wouldn't be an issue. At 9AM, I don't think crowds would really be an issue on the G either.
You also have the option of taking the bus. The B24 runs along Greenpoint Avenue, and brings you to 48th Street & Queens Blvd. Depending on where you work, you may be able to walk from there. You can track the bus using the
MTA Bus Time app.