A goal in each half saw the Scots do the double over the Croats to follow up their 1-0 win in Zagreb back in June with a 2-0 score line on home soil on Tuesday night.
"To get a clean sheet at home to Croatia and to win 2-0 speaks for itself really," said Hanley after the game.
"We are pleased with our night, it is a good result and a good end to the campaign. We can look forward to what comes now."
Scotland opened the scoring on 28 minutes, Robert Snodgrass heading home Charlie Mulgrew's cross from the left.
They drew confidence from that and added a deserved second after 73 minutes, Steven Naismith following up after Barry Bannan's penalty had been saved.
Hanley played the full match for the Scots and for an hour he was up against a familiar opponent in former Rover Nikola Kalinic.
The striker was one of the livelier forwards for the visitors, but was well shackled by the Scotland defence.
"Niko was in the first team just as I was coming up through the Ressies," added the defender.
"He's a good lad Niko so it was nice to see him again."
Scotland's first home win in Group A ensured they finished above Wales in fourth place.
Elsewhere, Rovers await news of an injury to Corry Evans in Northern Ireland's 1-1 draw with Israel.
The midfielder started the match in Tel Aviv but limped off after 24 minutes following a heavy collision.
Josh King wasn't involved as Norway ended their campaign with a 1-1 draw at home to Iceland.