I'm using a big wave leg rope it's much thicker than a short board leggy. It's a balin I think

As you've mentioned, 7ft of leggie actually does work ok on a 9ft board... I have a prone 8 foot fun gun I ride a bit, matched up with an 8ft leggie on bigger days. It's actually the board in my avatar.

Long leggie means the board it further away from you, and takes a tiny bit longer to retrieve. Also, to state the obvious, 10ft of leggie and 10ft of board is a 20ft kill zone! Which is roughly 6 metres.

Lots of leggie options, just go for the thicker chord. Most leggie companies have 5mm and 6mm chord for shortboards, and 7mm, 7.2mm and some have 8mm, for longboards, and SUP Boards. You'll find 8ft, 9ft, and 10ft lengths. The common short board length is 6ft to match up with the plethora of white "six ones" that are available.

I think Balin's ankle attachment is better than most....

Balin have been in the market for a very long time, and their products are very good. Australian company, but some products and materials come from China I believe. Same for the rest of the manufacturers though....

PS - I'll have a case of Coopers (another Aussie owned company). I have sent you a Seabreeze Email with my address for delivery !