ODI Registered Trainers can use the ODI Registered Trainer mark to create, market, sell and teach courses and training designed by the individual registered trainer.
The ODI Registered Trainer mark does not give license to train, market or brand courses created by the Open Data Institute, or other ODI Registered Trainers, without prior permission or agreement, which must be in writing.
Original content created by ODI Registered Trainers remains their intellectual property. Course content (not including course titles, or client confidential material) should be shared subject only, at most, to the requirement to the attribute and/or share-alike. (Source)
Successful trainers apparently can use a logo that matches the ODIs to promote their work, as a graphic badge; as far as a certification, any validation would be done by verifying with the ODI?
Plus that the "legal bit" has a quasi creative commons statement, though it's not identified as a license:
should be shared subject only, at most, to the requirement to the attribute and/or share-alike.