Can I skip 2.4.6 / 2.4.7 / 2.4.8 and go straight to 2.4.9?

Yes, Magento upgrades are cumulative, not stepped. You can compose-update from 2.4.4 → 2.4.9 in a single jump. Adobe explicitly supports skipping minor versions during the upgrade process.

What you cannot skip:

• The deprecation work from each intervening version. If 2.4.5 deprecated \Zend_Date and 2.4.6 removed it, your custom code still needs to update. Skipping versions doesn’t skip deprecations, it just delivers them all at once at upgrade time.
• The dependency cascade. Composer will resolve to the latest compatible versions of every dependency at once, which can mean cascade-failures across multiple modules. Doing one minor version at a time spreads the failure surface.
• Database migrations. All data:upgrade patches between your current and target versions run sequentially, in order. You don’t skip them; they all execute on first setup:upgrade.

My recommendation by version:

• 2.4.6+ → 2.4.9: jump direct, single-shot.
• 2.4.4 → 2.4.9: jump direct, but allocate 50% extra UAT time.
• 2.4.0 → 2.4.9: jump direct only if dev team is senior; otherwise step through 2.4.4 first.
• 2.3.x → 2.4.9: step through 2.4.4 first. The PHP + composer + framework cascade is too risky to do in one shot.