iMac Intel 24" EMC 2267 early 2009

[whambejambe]

If I install a SSD on that machine, can I install a newer OS on that HD?

 

[pldelisle]

If I install a SSD on that machine, can I install a newer OS on that HD?

No.

Your last resort is here :http://dosdude1.com/catalina/

If your mac falls in the compatibility list there is hope. If not, it’s dead. It has nothing to do with the HDD or SSD.

 

[Nguyen Duc Hieu]

If I install a SSD on that machine, can I install a newer OS on that HD?

Your iMac early 2009 must stick to with OS X El Capitan. Period.
I have one, too.

 

[Nguyen Duc Hieu]

By "newer OS", what OS are you thinking of?

 

[whambejambe]

By "newer OS", what OS are you thinking of?

High Sierra or Mojave

 

[pldelisle]

Well theoretically your iMac is in Dosdude’ list. So you could try to install a Patched version of Catalina and it should run correctly. You will get security updates for the next 2 years.