I would like to know is it safe to use my ipad without virus software installed on it

Yes, it is.

Yes, you can use it safely, unless it's hacked or jailbroken.

Most banks have their own apps. Also never let someone you don't know use your iPad.

To put virus on iPad, they need to have physical access to your iPad.

There is no real functioning Antivirus for iPad because currently there are no viruses that can affect an iPad.

The closed nature of the operating system prevents the Antivirus from installing and running itself, as well as preventing any Antivirus from being able to scan the iPad's file system in search of a virus.

So in short, usage of the iPAd is as safe as you make it.

Like has been said, don't bank in open networks, don't click on links in emails you don't recognize, don't browse sites that look shady or untrustworthy, etc...