You can install a single node Select cluster on less than 8 disks as long as the minimum datastore size is met. The 8-24 disk requirement is for production systems and is generally intended for I/O performance (on spinning disks) and disk/data protection (RAID5). If you're just setting up an eval/research system to check things out it'll work just fine.
Suggest you download the latest version (9.1GA) - the minimum datastore size for a single node evaluation install has been reduced (Single node > 1.3TB) and the webGUI is much better.
A final option is to download the single node export under Downloads->Product Evaluation. It ia an export of a prebuilt single node instance. This will allow you to avoid using the DeployVM entirely if you want.