1a Horse jumper finally making many nervous on street? (7) g???a??
9a Propeller needing special people to control it? (7) a???r??
2d Terrible danger in selling plant business (6,9).
????e? gardening
4d Keep tug (5) ????r
9 Aircrew - it seems a bit clunky, but I think you take the 's' for special out of 'screw/airscrew. The aircrew would control it. Does that make any sense?!