Hi Tony, thanks for the question!
It certainly wouldn’t be impossible to do this – but you would need a good understanding of PHP and WordPress development and indeed a good understanding of how WooCommerce functions.
If payment is by credit card and you configure the tickets as virtual/downloadable product types then in most cases they will ‘complete’ automatically. In that case you could then provide a link to download the generated PDF – though since they would then receive them in an email near-instantly this may be a moot point.
Alternatively, if due to other factors the order still doesn’t automatically become marked as ‘complete’ you could create code to make that change automatically and, once again, either provide a download link to the tickets or else simply roll with the existing email-based process.
Does that answer your question?