That article isn’t making any distinction between the A-50 and A-50u. I think that “9” number is the total of both. I haven’t been able to find any sources that confirm if the aircraft hit yesterday was an A-50 or an A-50u. If its an A-50u this loss is soooo much worse for Russia.

The A-50s are Soviet era analog electronics which are still useful, but not nearly as much as the modern version.

The A-50u is the upgrade modern variant much greater vision and capabilities with modern digital systems.

Here’s a better article on this plane and the difference in the versions

Here’s all of the known names on each and date of entry into service:

Possible active А-50 of the Russian Aerospace Forces:

• 43, tail number unknown, 1987.
• 51, tail number unknown, 1988.
• 46, tail number unknown, 1983 (most likely ‘old crate’).
• 50, tail number unknown, 1987.

Active А-50U of the Russian Aerospace Forces:

• 47, RF-92957, 1984.
• 33, RF-50602, 1984, ‘Vladimir Ivanov.’
• 37, RF-93966, 1988, ‘Sergey Atayants’ (destroyed).
• 41, RF-94268, 1988, ‘Taganrog’
• 45, RF-93952, 1989.
• 42, RF-50610, 1990.
• Unknown aircraft.