A person with only one kidney may have a normal level of about 1.8 or 1.9. Creatinine levels that reach 2.0 or more in babies and 10.0 or more in adults may indicate severe kidney impairment and the need for a dialysis machine to remove wastes from the blood.
Aside from kidney failure or azotemia; dehydration is another cause for elevated creatinine.
Your creatinine level of 1.7 is high but if you are asymptomatic and the other blood values are okay; I don't see any reason why you can't use the hot tubs. Use it judiciously and for short duration if you are hypertensive.
A better assessment of renal function is Creatinine Clearance. This is done with a urine specimen collected for 24 hours simultaneously with a serum creatine clearance. http://kidneydisease-creatinine.blogspot.com/2013/06/high-creatinine-17.html