Hi Carlito,
The behavior did change slightly between 7.x and 8.5. here's the note
from the relase notes for 8.5
Allowing Users to Toggle Between the Touchtone and Voice-Recognition Conversations
In Cisco Unity Connection 8.0, users were able to press 9 to switch from the voice-recognition conversation to the touchtone conversation. In Connection 8.5, that functionality has been enhanced. Now, when the user presses 9 while in the main menu of the conversation, the key press functions as a toggle between the voice-recognition and touchtone conversations. If users are assigned to the voice-recognition conversation and press 9 while in the main menu, they are switched to the touchtone conversation, and vice versa.
If you prefer that users press a different key to toggle between the conversations, use the Custom Keypad Mapping tool to assign a different key or keys. For instructions, see the "Custom Keypad Mapping Tool in Cisco Unity Connection 8.x" chapter of the System Administration Guide for Cisco Unity Connection Release 8.x, available at http://www.cisco.com/en/US/docs/voice_ip_comm/connection/8x/administration/guide/8xcucsagx.html.

Note
At any time while signed in to Connection, users who are assigned to the voice-recognition conversation can say "Touchtone conversation" to immediately switch to the touchtone conversation
http://www.cisco.com/en/US/docs/voice_ip_comm/connection/8x/release/notes/851cucrn.html#wp847640
Cheers!
Rob
"Celebration it's around us, every nations, all around us.
Singin' forever young, singin' songs underneath that sun" - K'naan