The Taliban were an indigenous rabble of fanatical seminary students. The Pakistani military dictator Zia and the Pakistani intelligence agency (the ISI) started throwing money (some CIA-derived, much more from the Saudis and Gulfies) at the Taliban, setting up training camps for them in Pakistan, enabling them to grow as a militia and a political force. Most of this growth was in the late phases of the expulsion of the Russians and their puppet government, and more so during the social upheavals that followed.

Al-Qaida had a more direct muj lineage. Binladen got his start as a bagman delivering Saudi money to the mujahideen. But Al-Qaida was a multinational organizaion, not rooted in Afghan society. The Taliban shared Sunni fundamentalist fanaticism with AQ, but in a Pushtu cultural context. For example, they turned a blind eye to such traditional Pushtu practices as buggering pubescent boys. The Taliban have also gone to great lengths to brutally oppress and sometimes murder people from other ethnic and religious groups within Afghanistan.

After the end of the Russian occupation, the main successor groups to the mujahideen were the various warlord-led militias that later formed the Northern Alliance. The Taliban fought against them.

So, while the CIA blowback narrative is partially true, the Pakistani meddling explanation is closer to the truth.