Short answer: It shouldn't really matter.
Longer answer: Though you should expect a clean upgrade to 10.0 from any 9.X version, you are safest upgrading 9.X -> 9.5.1 -> 10.0 -> 10.1.2, like the majority of SW customers. This is a well-worn upgrade path. NPM 9.5.1 provided a large number of important fixes to previous 9.X versions. These fixes were certainly incorporated into all later versions, but upgrading to 9.5.1 ensures that all updates to NPM are completed as cleanly as possible.
And, as with all upgrades, complete a full backup of your database, as described in "Creating Database Backups" and "Using SQL Server Management Studio" in the SolarWinds Orion NPM Administrator Guide, before attempting any upgrade.