If you press # after dialing the number, does the call go through immediately? If so, this is due to the interdigit timeout. If you simply have a dial peer with a destination of 9T, the UC520 is waiting to see if you are going to enter additional digits before it sends the call. You can either press # after the number or create dial peers with more specific matches. For example, for 7 digit local calls, you could have a dial peer similar to:

dial-peer voice 1 pots

destination-pattern 9[2-9]......

forward-digits 7

port 0/0/0

Hope this helps.

Brandon