Does ZigBee Smart Energy Profile 2.0 support meter data pushing from meters to a concentrator
I think you are getting confused, or confusing me, with some of your terminology. 

Devices = EndDevice - If that is what you mean, typically battery powered devices that sleep.

Concentrator = Coordinator - I assume you mean Coordinator, concentrator means something different in ZigBee and is only used in a certain routing scheme.

Poll = Data Request - An EndDevice can sleep and as such needs a parent. The parent can be a Router or the Coordinator and stores messages destined for the child EndDevice until it wakes and sends a Data Request to its Parent, this data Request is sometimes refered to as a "Poll". The Parent sends a MAC acknowledgement in response, with a "Frame Pending" bit to indicate to the EndDevice that it should stay awake to receive some queued messages. 

With ZigBee terminology out of the way; Yes, an EndDevice (or Coordinator/Concentrator or Router) can wake and send messages to the Coordinator (or any other device) at any time once it has joined the network and passed through the secure joining process, and has a parent to forward on the messages. The issue for an EndDevice is in the other direction, it will only receive and act on a message when it wakes and "Polls" the parent for any queued messages. The other issue is typically where to send the message, even if you are sending to the Coordinator and known it is network address 0x0000, you still do not know the EndPoint number (which is defined by the device manufacturer). There are various mechanism used to discover this, typically in SE a Match Descriptor request is used to discover the address/endpoint of a device supporting a particular cluster.

Regards,
TC.