I can't see calling here for an additional 1800 to get to 3000 with then only about 4000 left.
So to me it leaves shoving all-in or folding.
If you shove, I think you have near zero fold equity after the PF3B to 3000 done by the solid/conservative player you describe at UTG+1. He already did put 3000 in and he'd have only 4000 to add to call in a pot that would have, before his call, 10750 (your 7 000 + 6*25 of ante + 600 of blinds + his 3 000)... So he would have quite good calling odds if you were to PF4B shove all-in.
So if you shove, you have to seriously expect a call. Which leaves you to putting him on a PF3B range, to see if your 99 could be a favorite vs his range.
Versus a range of nearly 5%, which would be 77+,AK (all pocket pairs of 77 or more and all AK hands), you are only 41% favorite.
To reach 50/50 he would need to have a range of 7% (say 55+,AK,AQ).
So to me you don't have enough fold equity and if you want to "flip", I'm really not sure it's going to end up being a flip, because a solid/conservative player 3-betting you preflop from UTG+1 (4 players are still going to speak after him) must have a narrow range.
So, as "amigal" answered in the other answer, I think fold is a good idea : )