In all honesty your training will likely be fine. Cutting back a small amount on food will be all you need.
Adding more training could be detrimental if you have a well established sport specific routine so change this only under guidance or in consultation with your tennis coach. Doing otherwise could leave you unemployed.
Calorie cut would be minimal to ensure you have plenty of training energy, just a couple of hundred a day drop. More important to keep your training at its peak than rush fat loss.
To back me up here’s some math
18% of 88kg = 15.84 (16 for ease)
9% is by definition half this will say 7kg to be in the 8-9% range! which is below ideal athletic range, so be careful here.
7,700 calories per kilo so 69,300 to lose
200 calories a day drop will bring you to your target in 346.5 days, or just under a year which when doing professional sport training is nothing.

It is often best to go for the simplest option. Please speak to your coach however as some sports especially those were you need a lot of energy for long periods do not advice dropping below the 10% minimum athletic body fat level. If this is to be your career, it must come first above aesthetics.