This book constitutes the refereed post-conference proceedings of the 9th International Conference on Broadband Communications, Networks, and Systems, Broadnets 2018, which took place in Faro, Portugal, in September 2018. The 30 revised full and 16 workshop papers were carefully reviewed and selected from 68 submissions. The papers are thematically grouped as follows: Advanced Techniques for IoT and WSNs; SDN and Network Virtualization; eHealth and Telemedicine Mobile Applications; Security and Privacy Preservation; Communication Reliability and Protocols; Spatial Modulation Techniques; Hardware Implementation and Antenna Design.