Hi there 
we are a tech company that enables brands to place branded 3d objects into 3d experiences.
Technically we enable game publishers to integrate the objects we provide into their experience with our plugin. The object will be loaded from our platform into the publishers game for a limited time but we dont transfer the ownership.
My question: can we use objects that we bought from the asset store for this purpose under the commercial license?
Best
I am not a lawyer(IANAL).
Through your plugin, so a services sdk huh?
That is called out here Asset Store Terms of Service and EULA in section 2 sub-section 2 (or just 2.2). I would read the terms you’re agreeing to at the aforementioned link, Section 2 has the language you’re looking for.
2.2
“Licensor grants to the END-USER a non-exclusive, worldwide, and perpetual license to the Asset to integrate Assets only as incorporated and embedded components of electronic games and interactive media and distribute such electronic game and interactive media. Except for game services software development kits (“Services SDKs”), END-USERS may modify Assets. END-USER may otherwise not reproduce, distribute, sublicense, rent, lease or lend the Assets. It is emphasized that the END-USERS shall not be entitled to distribute or transfer in any way (including, without, limitation by way of sublicense) the Assets in any other way than as integrated components of electronic games and interactive media. Without limitation of the foregoing it is emphasized that END-USER shall not be entitled to share the costs related to purchasing an Asset and then let any third party that has contributed to such purchase use such Asset (forum pooling).”
You won’t get an authoritative answer here - you should ask a lawyer. If it were me, however, I’d say that you were not embedding the asset in a game - you are distributing the asset to enable your customers to embed it in their games. As such, you’re in breach of section 2.2 of the EULA as quoted by @landern.