From the NCAA Football 2009-2010 Rules & Interpretations:
SECTION 4. Opportunity To Catch a Kick
Interference With Opportunity
ARTICLE 1. A player of the receiving team within the boundary lines attempting to catch a kick, and so located that he could have caught a free kick or a scrimmage kick that is beyond the neutral zone, must be given an unimpeded opportunity to catch the kick (A.R. 6-3-1-III, A.R. 6-4-1-V and A.R. 6-4-1-X).
Seems to me that this means you can interfere without contact (as happened in that purdue game - the purdue player was standing right where the ball was to land, and our receiver wasn't able to catch it).
I think on your second point, if the player makes the catch then they weren't considered to be interfered with - or at least the officials don't call it unless the catch is muffed.