Only the first part was directed at you. The rest was for the OP.
Maxon also uses the term "clean boost" in the way that you did, but that's not really what a clean boost is... it's clean in the sense that it isn't distorted, but not a true clean boost because it's still going through the tubescreamer circuit. I think of things like the Keeley Katana as true clean boosts.
As far as whether it's true bypass or not, that depends on how you define true bypass. Maxon sometimes says it is and sometimes doesn't... because it doesn't use a 3PDT or 4PDT (OD-9 uses 4PDT) like most "True Bypass" pedals. Regardless, Maxon says it uses a DPDT switch wired in a special way that they claim produces improved resistance characteristics over the typical 3PDT true bypass, and that's why they still refer to it as true bypass sometimes..... Either way, no matter what you call it, the point is that it's extremely transparent & does not suck tone whether engaged or not... According to Maxon, the OD820 is their highest quality, least noisy, & most transparent tubescreamer.
To the OP:
They've also reintroduced the OD-820 as the VOP-9. The VOP-9 is supposed to have the same circuit as the OD-820, except more crammed together into a smaller enclosure and instead of always running at 18 volts like the OD-820, it can be switched back and forth between 9 volts and 18 volts. I like the OD-820 at 18 volts, so I'd opt for that over the VOP-9, but the VOP-9 is still an interesting option.
Read these:
http://www.maxonfx.com/Q_And_A.php
http://www.maxonfx.com/NewsOd820_2004LT.php
http://www.maxonfx.com/Nine_VOP9.php