ocspd using a lot of CPU and messing with browsers

I have a 2012 MacBook Pro (bought in 2014) running OSX 10.9.5

A few days ago Safari wouldn't load pages anymore- i used chrome for a bit until the same problem started appearing (and it was also messing with Mail's access to my email server)-I then realised it was to do with website certification, and shutting down the "ocspd" process temporarily solved the issue-sometimes for a minute, and sometimes it behaves for a few hours. However, it's always using more CPU than as I understand, it ever should, climbing into the 20% range in the background, even up to 50% sometimes, and up to 70% when it completely stops safari from being reponsive until ocspd is quit or force quit. I restarted the computer and after a few hours without issues the problem came back.

I should note, I have consistently been running safari with just over 20 tabs continually open for a few months now, though I never encountered this sort of issue before. That said even after reducing the number, the ocspd issue would return.

I should also note that recently Safari has been putting up Identity verification/certification popups for an increasing number of websites-usually to do with the ad tracking used by the websites-which I understand is due to them not bothering to support out of date browsers. Could my ocspd issue simply be due to having too old an OS, rather than it being broken?

I've seen a bunch of old community posts suggesting ocspd overrun issues have a history of happening on various Mac OS'.

So how do I solve my issue?

-Can I repair ocspd functions through some command line or file reset? Or, failing that, can I at least turn it off temporarily?

-I intend to upgrade my OS at some point later this summer, but am unable to in the next few weeks because I'm travelling. Would updating the OS solve the issue? (Ie would turning off certification until I upgrade be an option?)

-Or is this some OS corruption that would require me collapsing back to my previous time machine update from late May? (and, would backing up the system as it currently is on the same drive hamper my ability to do that?)

Thanks in advance for your help!