I formatted my mac (late 2009) and install macOS Sierra Version 10.12.6 latest version that i could install.
when I tryed to install photoshop from creative cloud it said that it is not compatible. so I contacted customer care and the tryied remotely to install an older version of photoshop CC but they could not as a message apear "Error code 41: Unable to access a critical file/directory".
finally they asked to cntact apple for the issue but when i contact them they wonder why i am contacting them.
Since you cannot install the current or older versions of Photoshop on your 2009 Mac after you reformatted the hard drive, the only other solutions I can think of are to upgrade your hardware and OS (buy a new Mac) or look for alternative software.