Hello Nash,
I can't tell you what makes you compliant as the data controller; compliance is a complex topic even for legal advisors. I highly recommend consulting one.
I can tell you that we believe Google is compliant as a data processor, since that's outlined in the privacy doc. We of course have encryption at rest/in transit/et al so that part should be covered.
I don't hear many developers asking about Instance ID in regards to compliance, but I can't say why. Maybe it would help to check out some of the materials in our
Play and
App Store disclosure guides; they might be enlightening on exactly what info you need to disclose and consider before you track.
☼, Kato