Can I install Prey remotely into my lost device?

Unfortunately this is not possible. Prey needs to be linked to a user account in order for it to work, and the only way of doing this is configuring Prey manually. Even if you pushed it remotely into your mobile devices via Google Play, you'd still need to link it to your  Prey account, so it wouldn't work.

If you have any remote desktop app on your device, such as LogMeIn, then you could install and configure Prey remotely, but that's the only available option for now.