I'm not 100% sure if this works with BitSharesX wallets but you can try:
Old Mac:
1) Fire up the client
2) File->Export Wallet
3) Copy resulting .json to a thumb drive or a lan disk
New Mac:
1) Fire up the 0.9.2 client
2) File->Import Wallet
3) Choose the .json and type in your passphrase.
If this works you're done with your old BitSharesX software.
If it doesn't work there's always the hard way:
Old Mac:
1) Fire up the client and login
2) Go to the advanced tab and type wallet_account_export_private_key <account_name> (syntax may be off but you can type help to get it)
3) Copy the private key for each account you want to migrate
New Mac:
1) Fire up the client and create a new wallet
2) In the upper right corner click the Account menu->advanced and then the console tab.
3) type: import and look for the command that looks like it's for importing WIF keys (sorry, don't have the client running right now).
4) Repeat step 3 for each private key.
I'm sure there is a better way.