This is a fold vs 3bb raise in reasonable game (all players have a clue) because there are 4 for more players to act who will play more or less perfectly vs you (they know utg range is tight so utg+1 shove is very tight). Even TT would be a fold if UTG range is 14-15% as it usually is.
Now the question is what the guy is doing with his 5bb raise. You can assume he is a fish and randomly spazzes with this big raise in which case 99 is close shove or that he is applying some non-retarded strategy in which case it's easy fold (general rule is that against bigger bets/raises you may play tighter than against small ones and not be worse off).
Buy for w/e you want. If you don't understand 30bb shoving you have no business playing 100bb game unless you feel like donating.