Get TYPO3 CMS! To get familiar with TYPO3 v9 LTS, the best thing is to download and try it out yourself.
"What's new?" Slides. Check out the what's new slide presentation for detailed highlights showing changes in the UI, and what's under the hood to get a complete picture.
TYPO3 v 9 ideos on TYPO3 YouTube - playlist. If it’s relevant, you can embed these videos directly into your post.
Analysis - TYPO3 v 9 LTS features (Google sheet).Want to take an even more detailed look? Here is an analysis of this new release, feature by feature.
Changelog. You can also review the changelog if you want to see the changes in detail. Keep in mind, if you're using the TYPO3 v9 LTS, you can use the "Extension Scanner" to review any breaking changes that affect your custom code. Cool!
TYPO3 CMS Roadmap. If you want to see the overall roadmap at any point.