Another complicated answer, and one that I can't answer yet for a 900er. I have flown 321's, highest gross weight version that I know of. Taking off full of PAX, no revenue cargo, right at max gross, we flew 4:45. That was with ICAO fuel requirements. Using FAA fuel requirements, with a very close alternate, maybe 5:30. Less passengers, more fuel, obviously it will fly farther. My company now has a bunch of 900er's. They fly them full, I believe significantly farther.
Most jets have extra fuel capacity. You can light load them and fly them farther. Airbus's website is usually quite optimistic for their aircraft. Ask the operator's who bought A340-200's how they worked out for long flights.
I prefer flying a 320 series to a 737, but the NG 737's are a bit more capable.