No one has asked the really obvious question here.................
What size tank is this 9" oscar in
/// I hope it's at least a 70 gallon tank (48x18x20)
Anything smaller and your asking for trouble. At a size of 9" and a body height of 4" your oscar still has a long way to go until it reaches it's adult size and any tank smaller than a 70 gallon will hamper it's growth.
Oscars IME are not fussy eaters!! I brought in 7 gold oscars several months ago.
They were in transit for 12 hours and were eating within one hour of being placed in their tank.
They were around 3" at that time and are now nearing 5". They share a 120 gallon tank with 9 F1 firemouths.
They are also nearing the size of being to big for 120 and are going to be placed in a 180 shortly.
Please do yourself and the fish a favor and find someone to either hold the fish or take them.
IMO artificial bacteria will not cycle your tank properly for this size fish!!
smb's suggestion of getting some aged gravel or filter material is a good one, but there again we're talking a 9" fish here and have no idea of the size of the pleco or the tank so it's really hard to say if even this method will work.
I wish you luck....as oscars are a great fish to have.
CM