Translation:He has not heard
On Wiktionary, this is the "not yet" case. See for yourself: https://en.wiktionary.org/wiki/vaa
-ja- should always be translated with "not yet"! :) (the possibility of it still happening exists; with -me- it simply did not exist in the past; there are no implications about the present or future as to whether it might/still will happen)
With "-me-" it has indeed existed in the past. -me- is always positive, never negative, and it does have a strong implication about the present, just as -ja- does.
The English present perfect tense also talks about the possibility of something happening in the future. Eg.
"I've never been to Paris" = It is still possible to go to Paris. "I never went to Paris" = The opportunity has been missed.
The word yet simply emphasises this future possibility in the same way that the word bado does, so I disagree with you. I think the arguments that it should always be thought of as "not yet" are written for speakers of American English who don't use the present perfect very consistently.