It does sound like there is a problem with your aggregation tasks. Is this a clean 9 (9.0.1?) install or an upgrade?
As noted in a previous answer, don't expect to see anything in Experience profile until you have identified some contacts. However I believe, you should still see data flow through in Experience Analytics & Path Analyzer.
Worth checking:
Marketing Definitions are deployed properly. Check your Solr instance by viewing Core Admin and ensuring the marketing definition indexes have documents populated. If not, redeploy your marketing definitions from the sitecore control panel and rebuild your indexes. Check the logs to make sure both of these processes don't fail in certain places.
There are no errors when the aggregation tasks are running (but I'm sure you would've seen that in logs already). I've seen in some migrations that the SQL user was not set correctly and needed to be manually fixed.
Check your path analyzer tree definitions etc are fully deployed in /sitecore/admin/pathanalyzer.aspx. They may need a rebuild too.
Rebuild your links databases before redeploying marketing definitions ;) As mentioned in the following answer, sometimes they do not appear to deploy properly if the links database is not up to date. Experience Analytics are not showing Online Interactions