The nine/seven lives reminds me of a query I saw somewhere else recently about being on cloud nine in Britain, seven in Germany, which was not answered, and which reminded me of the Norse/Germanic worlds of which there were nine or seven, according to where you lived. But whichever number that was, we're on the middle one. Bringing the Spanish into the confusion is interesting, but not at helpful.

Something to do with numerology, magic numbers or odd numbers, or prime numbers or...