PLT OF VFR AA5B FEELS ATC FAILED TO PROVIDE ADEQUATE VERTICAL SEPARATION WITH IFR ACR ACFT.

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OUR ACFT WAS IN CRUISE VFR UNDER RADAR ADVISORIES AT 9500 FT WITH A SCATTERED CLOUD LAYER BELOW US WITH TOPS OF 7000 FT. ATC ISSUED A HDG AND CLB INSTRUCTION TO THE AIRBUS AND INSTRUCTED THE AIRBUS TO STOP THEIR CLB AT 9000 FT DUE TO 'GRUMMAN TFC VFR AT 9500 FT.' THE AIRBUS HAD JUST DEPARTED ONE OF THE NYC AREA ARPTS. THE AIRBUS DID NOT RPT US IN SIGHT. ATC DID NOT CALL THE AIRBUS AS TFC TO US. WE SCANNED LOOKING FOR THE AIRBUS BUT WERE UNSUCCESSFUL DUE TO 1) A SCATTERED CLOUD LAYER BELOW US; AND 2) BEING UNSURE OF THE RELATIVE LOCATION OF THE AIRBUS. THE AIRBUS CAME INTO OUR SIGHT AND WE IMMEDIATELY CLBED AS A PRECAUTION. THE AIRBUS WAS APPROX 500 FT BELOW US AND PASSED DIRECTLY UNDER US. THE CTLR INSTRUCTED THE AIRBUS TO THEN CLB TO 15000 FT AS THE 'TFC WAS NO LONGER A FACTOR.' WE DID NOT RECALL THE AIRBUS RPTING US IN SIGHT; AND WE QUERIED THE CTLR AND SHE AND HER SUPVR DID NOT RECALL IF THE AIRBUS RPTED US IN SIGHT. I BELIEVE THAT THE AIRBUS SHOULD HAVE BEEN INSTRUCTED TO STOP THEIR CLB AT 8500 FT OR US INSTRUCTED TO CLB TO 10000 FT TO ENSURE 1000 FT OF VERT SEPARATION BTWN THE 2 ACFT UNDER RADAR IDENT BY ATC WHERE AT LEAST ONE OF THE ACFT DID NOT RPT THE OTHER IN SIGHT. IN THIS CASE NEITHER ACFT HAD RPTED THE OTHER IN SIGHT. CONTRIBUTING FACTORS WERE LIKELY: 1) THE SCATTERED CLOUD LAYER BELOW US; 2) THE CTLR'S FAILURE TO CALL THE AIRBUS TO US AS TFC; AND 3) A BUSY FREQ.