I'm not an expert on mag tapes, but it makes sense to me that 9-track tapes, where the tracks "line up" when the tape is wound onto a reel, suffer more "print-through" than helical scan tapes, where tracks are not aligned with those under them on a reel. I recall a suggestion that 9-track tapes should be mounted and rewound once in a while, to reduce print-through. We used Exabytes for disk backups for years, back when tape capacity exceeded disk capacity. I doubt I'll see that again, but, as noted I'm not an expert on mag tapes.