How can I return a UTF8 string from a hex representation in a latin9 database?

Hello. Hopefully I can explain myself

I have a database for a legacy application that requires an 8 bit database (i.e. the application itself won't function on a UTF8 database).

Looking at ways to extend the functionality to be able to handle a few specified fields in Unicode.

Had the idea to store a UTF8 string as either hex pairs or Base64 inside a VARCHAR field, which is fine. I can do that.

What needs to happen though, is to build a view, that will return the decoded hex (or b64) as a UTF8 string to a client which has specified client encoding UTF8.

I've tried various combinations of convert_from, and convert_to, and convert, but I just can't seem to get it to return the string a UTF8 select to the client.

So if I have this data:

select * from mytable;
mycolumn
------------------------------------------
ceb120ceb220ceb320ceb420ceb520cf83cf84

Then:

select convert_from(decode(mycolumn, 'hex')::bytea, 'utf-8') from mytable where usr='BATCH';

ERROR: character with byte sequence 0xce 0xb1 in encoding "UTF8" has no equivalent in encoding "LATIN9"

So the database encoding is still relevant , this is expected by the description of convert_from in the documentation of course.

Is there some combination of functions I can use to have a client select this column from this table in a LATIN9 database and get a UTF8 string back? Any thoughts appreciated, thank you.