There are no Antivirus Products available for iOS/iPadOS. Those that claim to provide AV protection are nothing more than “snake oil” - and should be avoided.
Due to the system architecture of iOS/iPadOS, unless jailbroken (don’t go there!), your iPad is not susceptible to traditional malware infection per-se. However, as with all computer systems, there are still vulnerabilities and exploits to which you remain vulnerable.
Browser-based attacks can largely be mitigated by installing a good, trusted, Content and Ad-blocking product. Given the age of your iPad - and the diminishing availability of compatible App for older devices pre-dating iOS 11/12 - choices are very limited. However, in this case you’re in luck!
One of the very best and most respected within the Apple App Store - designed for iPad/iPhone that remains compatible with iOS 9.x, is 1Blocker Legacy:
https://apps.apple.com/gb/app/legacy/id1025729002
1Blocker Legacy is highly configurable and effective in blocking browser-based attacks and unwanted content. This blocker App does not rely upon an external proxy-service of dubious provenance. All processing takes place on your device - and contrary to expectations, Safari will run faster and more efficiently.
Unwanted content is not simply filtered after download (a technique used by basic/inferior products), but instead undesirable embedded content blocked form download. A further benefit on metered services, such as cellular connections where you data may be capped or chargeable, this not only improves speed but also saves you money.
A further measure to improve protection, that is independent of iOS version, is to use a trusted Recursive DNS Service in preference to automatic settings. This can either be set on a per-device basis in Settings, or can be set-up on your home Router. I strongly recommend using one of the following services - for which IPv4 and IPv6 server addresses are listed:
Quad9 (recommended)
9.9.9.9
149.112.112.112
2620:fe::fe
2620:fe::9
OpenDNS
208.67.222.222
208.67.220.220
2620:0:ccc::2
2620:0:ccd::2
Cloudflare+APNIC
1.1.1.1
1.0.0.1
2606:4700:4700::1111
2606:4700:4700::1001
Use of the above DNS services will help to shield you from “known bad” websites and URLs - and when used alongside 1Blocker, provides defense in depth.
I hope this information proves to be helpful.