The general rumors have pointed to the new Nexus 9 tablet being released sometime within the next couple weeks or so.
The Nexus 6 still hasn't found it to the FCC, but it looks as though the HTC Nexus 9 has just passed the FCC.
There isn't a huge amount of information in the FCC filing that gives away the fact that this is the Nexus 9. But, the listing does note that this is an HTC tablet, and there are no other HTC tablets that we know of in development, meaning this is almost definitely the Nexus 9.
The only specs that can be taken from the filing are that the tablet has Bluetooth, NFC, and 802.11ac, and will come in 16 and 32GB variants. Rumors have said that the new Nexus tablet will also feature an 8.9-inch 1440x2560 display, a 64-bit Tegra K1 SoC, 3GB of RAM, a 16-megapixel camera, and will likely launch with Android L.