Bluetooth problems can often have various causes. But usually, the latency shouldn’t be that high. In terms of hardware, this could have to do with the Bluetooth dongle you are using. Apart from that you can only try to update max2play to the latest beta and reinstall bluetooth.
Then you should install the Wave Input Fix in the Squeezebox Server tab (depending on which LMS version you are using). To adjust the buffer size of the stream, go to the Squeezebox server settings under advanced/network and change the radio station buffer seconds or timeout.