<p>This proceeding in MDPI is a selection of papers presented at the 9th International Conference on Time Series and Forecasting. The main topics of this conference focus on the analysis and foundations of time series (a time series can be defined as a collection of observations of a variable recorded sequentially over time). Time series and forecasting tools are used in many fields of science with a particular focus on ITISE (as reflected in the papers in this proceedings) on econometrics economics and marketing forecasting in energy and economic indices forecasting in meteorology etc. ITISE 2024 aims to provide scientists engineers faculty and students with a discussion forum for the latest ideas and findings in the areas of foundations theory models and applications for interdisciplinary and multidisciplinary research encompassing disciplines of computer science mathematics statistics forecasting econometrics etc. in the field of time series analysis and forecasting. Therefore ITISE 2024 solicits high-quality original research papers (including significant works in progress) on all aspects of time series analysis and forecasting to promote the generation and development of new computational techniques and methods in the field of time series analysis and forecasting.</p>