Not for Valencia in their current situation. Munir will have to score around 15-20 La Liga goals for them to seriously consider executing his buy option. And I don't see that happening with Prandelli clearly prefering Rodrigo as their first choice striker and there are also rumours that he wants Italian forward (Gabbiadini, Cassano) to join them in January.
And for next summer I've read that Mendes is trying hard to get another of his players to Valencia (some young Portuguese forward, the name escaped me, sorry). So I think it's very likely (I'll say more than 90%) we'll get Munir back.