Have you looked at the posts here and here?
I have a 1703 with 9.5.7.94 and it also failed to upgrade to 1709. The very short version of the story is that the upgrades to 1703 were near 100% successful. Upgrading to 1709 is almost 100% failure. Note that running the 1709 manually using the same command as in the fixlet is always successful.
It would be interesting to learn if anyone from IBM performed an upgrade from 1703 to 1709 successfully.