Assuming paradise refers to heaven, since the only 2 other places in the Bible that use the word paradise refers to heaven, that would mean that the thief was raptured to heaven before Jesus who, as was pointed out, didn't go up to heaven yet. Assuming still that the thief was raptured up with everyone else worthy in Abraham's Bosom, which would imply they were judged which doesn't occur until the last day, Revelation which was written decades later speaks of a first and second resurrection. If the first happened on the day Jesus died, then the wording should have been, Blessed is he who hath taken part in the first resurrection, past tense, since it already occured.

Paradise in that verse therefore does not refer to heaven but Abraham's Bosom.