NO expert on taxes etc but as far as I know it had nothing to do with 9/11. Just a fundamental way the revenue laws alligned with international standards. Also prevented many of the flippers (property tri-partheid alliance) type deals from making super cash amounts without decalring income for taxes etc. This was an add-don to the 97/98 ammendment where you could buy assets in CC etc with no transfer taxes etc. Basically just an extra revenue strem for SARS.
Nope, the 1 oct date was if you did not have accurate records or you just accepted the rating of asset as per SARS assesment for that date. If you can proove your asset is lower and when you bought it with expected market conditions you could actually rate your asset lower. But you had to decalre and sign a form lodging it with SARS to the effect. Many people just accepted the SARS value and left it at that and many people actually benefited from this structure on value. Few "savy" people did a decalration and lowered there CGT asset value effectively shooting themselves in the foot. Rather had to value your assets higher then when you sell your CGT is asset value less sale price. Thus Higher asset value lower CGT. Many other tricks to it but thats the basic.