what i would do first is to read
this because it shows some methods to repairing discs provided they havnt been run over by a truck or something. after that i would try several image making softwares because some are able to read better than others so while you may get errors in one, you might not in another. usually if it stops prematurely then the disc has unreadable sectors. again, some programs will be able to read something that another may not so dont give up after one program fails. what i often use is ISObuster but there are many others out there that are just as good, read
this thread to get some ideas on what to use and how to use them. generally if a game does not run correctly on a real psx, be it a freeze or whatever, it will probably not work on an emulator either. in truth everything really depends on how bad the damage actually is, if the damage is extreme then there is little you can do short of buying a new copy.
as for what you can do as an alternative, downloading an image is always illegal regardless of if you own it or have previously owned it since what you are essentially doing is using an image that came from someone elses disc. legally, any image you have must come from your own discs. now, im not saying that you cant try doing that, its up to you really but imo i dont really suggest it not only because of the legal aspect but also because images you find on the net are usually not done right and working with them is a waste of time for the most part.
basically the majority of them are not made in a good format for psx games and by that i mean they often lack the subchannel which is needed for most games to work correctly. alot of them dont include the cdda audio either. im not trying to make you feel bad or anything im just saying that it just isnt really worth it because you are never sure what it is you are going to get and there is really no point of trying to use something that is potentially infeior to the real thing. if you want some places where you can buy the game i suggest amazon or ebay.
and just so you know, you mentioned ff9 as one of the games you want to play, im not sure if you are aware of this but you need to use epsxe 1.5.2 for that game to work correctly, it has an issue with 1.6.0 that almost always causes a lockup at a specific point. chrono cross has issues with 1.6.0 as well so if you want to play that game, use 1.5.2 and enable the "odd/even bit hack" game fix which can be found in the video plugin config under the game fixes section. version 1.7.0 is in its beta testing phase right now and from what time i have spent with it, this issue has been corrected but for now you will need to use 1.5.2 until the new version is released.