Coastal Communities Ocean Acidification Act of 2017 This bill amends the Federal Ocean Acidification Research and Monitoring Act of 2009 to require the National Oceanic and Atmospheric Administration (NOAA) to conduct and update at least once every seven years an ocean acidification coastal community vulnerability assessment with a corresponding public report. The assessment must identify: (1) U.S. coastal communities that are most dependent on coastal and ocean resources that may be impacted by ocean acidification; (2) the nature of those communities' social and economic vulnerabilities; (3) impacts from changes in ocean and coastal marine resources that are not managed by the federal government; and (4) key knowledge gaps where research could be devoted to better understand the possible ocean acidification impacts, risks, threats, and possible adaptation strategies for the communities. In carrying out the ocean acidification coastal community vulnerability assessment, NOAA must collaborate with state, local, and tribal government entities that are conducting or have completed vulnerability assessments, strategic research planning, or other similar activities related to ocean acidification and its impacts on coastal communities. NOAA's ocean acidification program is expanded to include an ongoing mechanism that allows affected industry members, coastal stakeholders, non-federal resource managers, regional environmental monitoring programs, indigenous knowledge groups, and outside scientific experts not employed by the federal government to provide input on research, data, and monitoring necessary to support on-the-ground management, decision making, and adaptation related to ocean acidification and its impacts. The strategic plan for ocean acidification research and monitoring developed by the Joint Subcommittee on Ocean Science and Technology of the National Science and Technology Council must make recommendations for research to address the key knowledge gaps identified in the community vulnerability assessment report.