As I understand, the holes are irregularly shaped, which is consistent with shrapnel damage rather than bullet wholes. Also, SU-25 can’t reach the height of the jetliner to shoot cannons.
Russians did it
Some might disagree. Russia Says Has Photos Of Ukraine Deploying BUK Missiles In East, Radar Proof Of Warplanes In MH17 Vicinity
On topic I believe it was a BUK missile. Who fired it is still to be determined. Where's our proof the Russian did it other than some carttonish audio tapes put together in Kiev's basement.