Again if your profile is public then you can see friends, games and achievements.
This has taken me over a year (on and off) to code and is now in public beta.
Checked the Xbox app and it shows I'm at level 81 now like it should.
It says at the bottom of the True Achievements website that they are a member of the Xbox LIVE Community Developer Program.
That leads me to believe that the XCDP does give information about achievements.
To date it has served nearly 2,000 requests and growing.
I am still working on optimising this script and it should only get better in time.