Rocksmith

To achieve rank 9, you must get 10 million rocksmith points (rsp). While it is true that during rehearsal, you only get rsp for the increase in your score for a particular song, you get full points for all songs performed at an event. My suggestion, then, is to edit the events to include songs you can easily score lots of points on. If you've already got a high score (over 100k) you'll most likely be prequalified and won't have to rehearse at all -- go straight to the event. Good luck and have fun.

I was able to get this by using the max 8 songs and attempting songs where either I have never done them before or where I thought I could get 100k points without having done so before. I used the megadeth DLC and didn't have any trouble with my detection but it was sometimes out of sync with what I was playing.

I personally did well with these songs (some are dlc).

Muse - Unnatural Selection
Heart - Barracuda
Megadeth - Public Enemy
Red Fang - Number Thirteen
Kings of Leon - Use Somebody
Soundgarden - Outshined
Red Hot Chilli Peppers - Higher Ground
Velvet Revolver - Slither

I found I would do best with songs I actually like hearing repeatedly. When playing try to hit every note in time and hold a little extra long for held notes that way you get a sustain bonus. If you get each note in time in a phrase you should also get a bonus. If you are able to get the phrase timing down for groove bonuses and the held notes for sustain bonuses you should be able to get a double encore. This will allow you to get the achievement quicker than you would otherwise. I averaged between 500k and 1.2 million points doing it this way each time with the 8 songs above.

To achieve rank 9, I recommend not only extending the setlist to it's max of 8 songs, but to play songs you haven't played yet. If you max out on a version of a song (combo, combo 2, chords), then play one you have 0 on. It will make your rank meter rise a lot faster. DLC will help give you more to choose from, but some of the detection in the DLC is sketchy in my opinion.