Mike, we do not delete the previous versions while the EAP program is open.
To download TeamCity 9.0 EAP1 (build 31423), use the required installation package:
http://download.jetbrains.com/teamcity/eap/TeamCity-31423.exe
http://download.jetbrains.com/teamcity/eap/TeamCity-31423.tar.gz
http://download.jetbrains.com/teamcity/eap/TeamCity-31423.war