Nope. 30k is easy for quite a few.
Not for manpads.
The best, the latest Stinger missiles, can get to about 26,000, The best Russian does around 22,000 feet.
There are definitely AAW missile systems that can get to 30,000 feet, but not man portable ones.
IMHO, a bomb seems most likely at this point. But the others have to be explored.
im not very familiar with the details of shoulder fired weapons, but would there be a visible trail as it streaked towards the plane? again just an honest question...
Which ones?