The BTC core wallet lets me choose my own passphrase with 12-16 words. The latest would be late January, early February 2009. What wallet was I using? I can't find a reference online. Everyone says that passphrases weren't used until 2013. I am trying to get my wallet back. I now remember my passphrase.
I believe the only possible answer for this time (assuming you mean 2009, no wallets existed before then with recovery mnemonics) is that the wallet was blockchain.info. Different to now, at the time it used a "recovery mnemonic", which was an encoding of your password rather than the keys in your wallet. Unfortunately if this is the case you need to also know either the 'wallet identifier' (looks like
fbb4b1dd-1b30-4cc2-b745-b586e4f3cb57), or the original