News,
Your timing is pretty good, but most of these aren't the sharpest. Actually, on one of the night shots (#2) your shutter speed was OK (1/640s) but the shot still isn''t crisp. On others you shutter speed is WAY too low (1/250s - 1/320s), plus, you have -1/3 stop EC: why was this? Your shots are already underexposed - I'm guessing this was a mistake?
The daytime shots are a little better, though the timing on 4 is too late, and 5 should be taken from the end of the field (or wait for the runner to turn your way) so we'd be able to see his face. Also, watch your horizons; 3 and 4 or a little off, and 5 is quite a bit tilted.
To answer your question, yes, Noise Ninja is worthwhile. Shooting at ISO1600 is a piece of cake, and even ISO3200 is acceptable.
Also, I would never shoot night football without a flash unless it was at an NCAA/Pro stadium (where flash isn't allowed, anyway). The light is just too dim to make it worth my time.