I think that would be ok, Halo. But if you then passed your cherry 920 around for others to use to get more points, that would be illegal.
Here are the rules from the HWbot site. Joint bench sessions are explained (bold below).
4. Lending hardware, hardware sharing This in a delicate subject as we have to trust on the honesty of those participating at the HWbot that they are indeed using their own hardware and not sharing a golden sample CPU or VGA card.
Let’s start with what is allowed to be shared: everything… except:
- VGA may not be shared for 3D Benchmarks
- CPU may not be shared for 2D Benchmarks
Bench session with more than 1 person:
- post result to account of owner of the hardware (3d: vga, 2d: cpu)
- when sli bench with two owners (each one card) post result to one account (you can chose which account)
-
FORBIDDEN: post multiple results of the same session spread over different accounts
-
FORBIDDEN: share cpu on 2D and/or gpu on 3D benches with team members to gain more points.

While the rules are quite simple and straightforward, enforcing them isn’t. If you are having a joint benchmark session, provide as much proof and information as possible when you submit a new HWBot score, which shows you were using your own hardware for the benchmark in question, a photo with a paper showing your nickname and the product serial number is good way to do this.