Make sure you fulfill below conditions
VX9000 must NOT be used before imported to AWS
VX9000 does NOT support any VHD changes once imported to AWS
In other words – you have to scale the VHD size before deploying the VX to AWS without even logging into it.
Once the installation of VX9000 is done, you shall immediately start the import process as described in How to prepare the environment to install VX9000 on Amazon EC2 cloud?