I don't see how. Basic H6 can hold some 30 tons of fuel, and can on top of that carry some 10 tons of weapon payload. Y9's mtow weight minus the empty weight gives little under 40 tons. So similar payloads of fuel if both are made into tanker variant. Y9 should be somewhat more fuel efficient so it'd use less fuel for itself, meaning more is left for the offload. But that should be several tons, not 10 tons more. Figures on Y9 are kind of scarce so maybe it has higher mtwo and indeed it could go even over 5 tons, maybe even approach 10.
But then there's H6K, currently in production. It may have greater mtow and its engines use less fuel. It too could be made into a tanker variant. That may again put it to parity with a notational y9 tanker.
